Merged VRT work-in-progress from eb/vrt2 (11518:11598) into trunk.

Passes distcheck.


git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@11600 221aa14e-8319-0410-a670-987f0aec2ac5

55 files changed, 5258 insertions, 0 deletions

diff --git a/config/Makefile.am b/config/Makefile.am
index b921ec510..d6a3ad393 100644
--- a/config/Makefile.am
+++ b/config/Makefile.am
@@ -67,9 +67,11 @@ m4macros = \
 	grc_gr_trellis.m4 \
 	grc_gr_usrp.m4 \
 	grc_gr_video_sdl.m4 \
+	grc_gr_vrt.m4 \
 	grc_gr_wxgui.m4 \
 	grc_mblock.m4 \
 	grc_gruel.m4 \
+	grc_vrt.m4 \
 	gr_check_createfilemapping.m4 \
 	gr_check_mc4020.m4 \
 	gr_check_shm_open.m4 \
diff --git a/config/grc_gr_vrt.m4 b/config/grc_gr_vrt.m4
new file mode 100644
index 000000000..ff2d06347
--- /dev/null
+++ b/config/grc_gr_vrt.m4
@@ -0,0 +1,38 @@
+dnl Copyright 2008,2009 Free Software Foundation, Inc.
+dnl 
+dnl This file is part of GNU Radio
+dnl 
+dnl GNU Radio is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 3, or (at your option)
+dnl any later version.
+dnl 
+dnl GNU Radio is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+dnl GNU General Public License for more details.
+dnl 
+dnl You should have received a copy of the GNU General Public License
+dnl along with GNU Radio; see the file COPYING.  If not, write to
+dnl the Free Software Foundation, Inc., 51 Franklin Street,
+dnl Boston, MA 02110-1301, USA.
+
+AC_DEFUN([GRC_GR_VRT],[
+    GRC_ENABLE(gr-vrt)
+
+    dnl Don't do gr-usrp if gnuradio-core or vrt skipped
+    GRC_CHECK_DEPENDENCY(gr-vrt, vrt)
+    GRC_CHECK_DEPENDENCY(gr-vrt, gnuradio-core)
+
+    AC_CONFIG_FILES([ \
+        gr-vrt/Makefile \
+	gr-vrt/gnuradio-vrt.pc \
+        gr-vrt/src/Makefile \
+        gr-vrt/src/run_tests \
+    ])
+
+    GRC_BUILD_CONDITIONAL(gr-vrt,[
+	dnl run_tests is created from run_tests.in.  Make it executable.
+	AC_CONFIG_COMMANDS([run_tests_vrt], [chmod +x gr-vrt/src/run_tests])
+    ])
+])
diff --git a/config/grc_vrt.m4 b/config/grc_vrt.m4
new file mode 100644
index 000000000..d473c5581
--- /dev/null
+++ b/config/grc_vrt.m4
@@ -0,0 +1,51 @@
+dnl Copyright 2008,2009 Free Software Foundation, Inc.
+dnl 
+dnl This file is part of GNU Radio
+dnl 
+dnl GNU Radio is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 3, or (at your option)
+dnl any later version.
+dnl 
+dnl GNU Radio is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+dnl GNU General Public License for more details.
+dnl 
+dnl You should have received a copy of the GNU General Public License
+dnl along with GNU Radio; see the file COPYING.  If not, write to
+dnl the Free Software Foundation, Inc., 51 Franklin Street,
+dnl Boston, MA 02110-1301, USA.
+
+AC_DEFUN([GRC_VRT],[
+    GRC_ENABLE(vrt)
+
+    dnl If execution gets to here, $passed will be:
+    dnl   with : if the --with code didn't error out
+    dnl   yes  : if the --enable code passed muster and all dependencies are met
+    dnl   no   : otherwise
+    if test $passed = yes; then
+	dnl Needed for vrt_socket_opener
+	AC_CHECK_HEADERS(arpa/inet.h byteswap.h linux/if_packet.h sys/socket.h sys/un.h)
+    fi
+    if test $passed != with; then
+	dnl how and where to find INCLUDES and LA
+	VRT_INCLUDES="-I\${abs_top_srcdir}/vrt/include"
+        VRT_LA="\${abs_top_builddir}/vrt/lib/libvrt.la"
+    fi
+
+    dnl Include the vrt INCLUDES and LA
+    AC_SUBST(VRT_INCLUDES)
+    AC_SUBST(VRT_LA)
+
+    AC_CONFIG_FILES([
+        vrt/Makefile
+        vrt/vrt.pc
+        vrt/include/Makefile
+        vrt/include/vrt/Makefile
+        vrt/lib/Makefile
+        vrt/apps/Makefile
+    ])
+
+    GRC_BUILD_CONDITIONAL(vrt)
+])
diff --git a/configure.ac b/configure.ac
index 25b183027..1764b46ab 100644
--- a/configure.ac
+++ b/configure.ac
@@ -338,8 +338,10 @@ GRC_GNURADIO_CORE
 GRC_MBLOCK			dnl this must come after GRC_GRUEL
 GRC_USRP
 GRC_USRP2
+GRC_VRT
 GRC_GR_USRP			dnl this must come after GRC_USRP
 GRC_GR_USRP2
+GRC_GR_VRT
 GRC_GR_GCELL			dnl this must come after GRC_GCELL and GRC_GNURADIO_CORE
 GRC_GR_MSDD6000	
 GRC_GR_AUDIO_ALSA
diff --git a/gr-utils/src/python/Makefile.am b/gr-utils/src/python/Makefile.am
index b58faa9bf..65cbd536c 100644
--- a/gr-utils/src/python/Makefile.am
+++ b/gr-utils/src/python/Makefile.am
@@ -44,6 +44,7 @@ bin_SCRIPTS = \
     gr_plot_iq.py \
     gr_plot_short.py \
     lsusrp \
+    qr_fft.py \
     usrp_fft.py \
     usrp_oscope.py \
     usrp_print_db.py \
diff --git a/gr-utils/src/python/qr_fft.py b/gr-utils/src/python/qr_fft.py
new file mode 100755
index 000000000..c2f06d715
--- /dev/null
+++ b/gr-utils/src/python/qr_fft.py
@@ -0,0 +1,505 @@
+#!/usr/bin/env python
+#
+# Copyright 2004,2005,2007,2008,2009 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+# 
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+# 
+
+from gnuradio.wxgui import forms
+from gnuradio import gr, gru
+from gnuradio import vrt
+from gnuradio import eng_notation
+from gnuradio.eng_option import eng_option
+from gnuradio.wxgui import stdgui2, fftsink2, waterfallsink2, scopesink2, form, slider
+from gnuradio.gr import pubsub
+from optparse import OptionParser
+import wx
+import sys
+import numpy
+import time
+
+class app_top_block(stdgui2.std_top_block, pubsub.pubsub):
+    def __init__(self, frame, panel, vbox, argv):
+        stdgui2.std_top_block.__init__(self, frame, panel, vbox, argv)
+        pubsub.pubsub.__init__(self)
+        self.frame = frame
+        self.panel = panel
+        
+        parser = OptionParser(option_class=eng_option)
+        #parser.add_option("-e", "--interface", type="string", default="eth0",
+        #                  help="select Ethernet interface, default is eth0")
+        #parser.add_option("-m", "--mac-addr", type="string", default="",
+        #                  help="select USRP by MAC address, default is auto-select")
+        #parser.add_option("-A", "--antenna", default=None,
+        #                  help="select Rx Antenna (only on RFX-series boards)")
+        #parser.add_option("-d", "--decim", type="int", default=16,
+        #                  help="set fgpa decimation rate to DECIM [default=%default]")
+        #parser.add_option("-f", "--freq", type="eng_float", default=None,
+        #                  help="set frequency to FREQ", metavar="FREQ")
+        #parser.add_option("-g", "--gain", type="eng_float", default=None,
+        #                  help="set gain in dB (default is midpoint)")
+        parser.add_option("-W", "--waterfall", action="store_true", default=False,
+                          help="Enable waterfall display")
+        parser.add_option("-S", "--oscilloscope", action="store_true", default=False,
+                          help="Enable oscilloscope display")
+	parser.add_option("", "--avg-alpha", type="eng_float", default=1e-1,
+			  help="Set fftsink averaging factor, default=[%default]")
+	parser.add_option("", "--ref-scale", type="eng_float", default=1.0,
+			  help="Set dBFS=0dB input value, default=[%default]")
+        parser.add_option("--fft-size", type="int", default=1024,
+                          help="Set number of FFT bins [default=%default]")
+        parser.add_option("--samples-per-pkt", type="int", default=0,
+                          help="Set number of SAMPLES-PER-PKT [default=%default]")
+        parser.add_option("", "--ip-addr", type="string", default="192.168.10.2",
+                          help="IP address default=[%default]")
+        (options, args) = parser.parse_args()
+        if len(args) != 0:
+            parser.print_help()
+            sys.exit(1)
+	self.options = options
+        self.show_debug_info = True
+        
+        self.u = vrt.quadradio_source_32fc(options.ip_addr,
+                                           int(62.5e6), options.samples_per_pkt)
+        #self.u.set_decim(options.decim)
+        
+        #input_rate = self.u.adc_rate() / self.u.decim()
+        input_rate = int(120e6/4)
+        
+        if options.waterfall:
+            self.scope = \
+              waterfallsink2.waterfall_sink_c (panel, fft_size=1024, sample_rate=input_rate)
+        elif options.oscilloscope:
+            self.scope = scopesink2.scope_sink_c(panel, sample_rate=input_rate)
+        else:
+            self.scope = fftsink2.fft_sink_c (panel,
+                                              fft_size=options.fft_size,
+                                              sample_rate=input_rate, 
+					      ref_scale=options.ref_scale,
+                                              ref_level=20.0,
+                                              y_divs = 12,
+					      avg_alpha=options.avg_alpha)
+
+        self.connect(self.u, self.scope)
+
+        self._build_gui(vbox)
+	self._setup_events()
+	
+        # set initial values
+
+        #if options.gain is None:
+        #    # if no gain was specified, use the mid-point in dB
+        #    g = self.u.gain_range()
+        #    options.gain = float(g[0]+g[1])/2
+
+        #if options.freq is None:
+        #    # if no freq was specified, use the mid-point
+        #    r = self.u.freq_range()
+        #    options.freq = float(r[0]+r[1])/2
+            
+        #self.set_gain(options.gain)
+
+	#if options.antenna is not None:
+        #    print "Selecting antenna %s" % (options.antenna,)
+        #    self.subdev.select_rx_antenna(options.antenna)
+
+        if self.show_debug_info:
+        #    self.myform['decim'].set_value(self.u.decim())
+            self.myform['fs@gbe'].set_value(input_rate)
+        #    self.myform['dbname'].set_value("0x%04X" % (self.u.daughterboard_id(),)) # FIXME: add text name
+            self.myform['baseband'].set_value(0)
+            self.myform['ddc'].set_value(0)
+
+        #if not(self.set_freq(options.freq)):
+        #    self._set_status_msg("Failed to set initial frequency")
+
+    def _set_status_msg(self, msg):
+        self.frame.GetStatusBar().SetStatusText(msg, 0)
+
+    def _build_gui(self, vbox):
+
+        def _form_set_freq(kv):
+            return self.set_freq(kv['freq'])
+            
+        vbox.Add(self.scope.win, 10, wx.EXPAND)
+        
+        # add control area at the bottom
+        self.myform = myform = form.form()
+        hbox = wx.BoxSizer(wx.HORIZONTAL)
+        hbox.Add((5,0), 0, 0)
+        myform['freq'] = form.float_field(
+            parent=self.panel, sizer=hbox, label="Center freq", weight=1,
+            callback=myform.check_input_and_call(_form_set_freq, self._set_status_msg))
+
+        hbox.Add((5,0), 0, 0)
+        #g = self.u.gain_range()
+
+	# some configurations don't have gain control
+	if 0 and g[1] > g[0]:
+    	    myform['gain'] = form.slider_field(parent=self.panel, sizer=hbox, label="Gain",
+                                           weight=3,
+                                           min=int(g[0]), max=int(g[1]),
+                                           callback=self.set_gain)
+
+        hbox.Add((5,0), 0, 0)
+        vbox.Add(hbox, 0, wx.EXPAND)
+
+        self._build_subpanel(vbox)
+
+    def _build_subpanel(self, vbox_arg):
+        # build a secondary information panel (sometimes hidden)
+
+        # FIXME figure out how to have this be a subpanel that is always
+        # created, but has its visibility controlled by foo.Show(True/False)
+        
+        def _form_set_decim(kv):
+            return self.set_decim(kv['decim'])
+
+        if not(self.show_debug_info):
+            return
+
+        panel = self.panel
+        vbox = vbox_arg
+        myform = self.myform
+
+        #panel = wx.Panel(self.panel, -1)
+        #vbox = wx.BoxSizer(wx.VERTICAL)
+
+        hbox = wx.BoxSizer(wx.HORIZONTAL)
+        hbox.Add((5,0), 0)
+
+        myform['decim'] = form.int_field(
+            parent=panel, sizer=hbox, label="Decim",
+            callback=myform.check_input_and_call(_form_set_decim, self._set_status_msg))
+
+        hbox.Add((5,0), 1)
+        myform['fs@gbe'] = form.static_float_field(
+            parent=panel, sizer=hbox, label="Fs@GbE")
+
+        hbox.Add((5,0), 1)
+        myform['dbname'] = form.static_text_field(
+            parent=panel, sizer=hbox)
+
+        hbox.Add((5,0), 1)
+        myform['baseband'] = form.static_float_field(
+            parent=panel, sizer=hbox, label="Analog BB")
+
+        hbox.Add((5,0), 1)
+        myform['ddc'] = form.static_float_field(
+            parent=panel, sizer=hbox, label="DDC")
+
+        hbox.Add((5,0), 0)
+        vbox.Add(hbox, 0, wx.EXPAND)
+        ##### db control stuff #####
+        self.subscribe('cal_div_lo_freq', lambda x: self.u.set_lo_freq(x) and time.sleep(0.01))
+        self.subscribe('cal_div_lo_freq', self.u.set_center_freq) #TODO should be combined with set lo freq
+        self.subscribe('cal_div_cal_freq', lambda x: self.u.set_cal_freq(x) and time.sleep(0.01))
+        self.subscribe('db_ctrl_atten0', self.u.set_attenuation0)
+        self.subscribe('db_ctrl_atten1', self.u.set_attenuation1)
+        self.subscribe('sys_beaming', self.u.set_beamforming)
+        #self.subscribe('db_ctrl_10db', self.u.set_10dB_atten)
+        self.subscribe('db_ctrl_adcgain', self.u.set_adc_gain)
+        self.subscribe('db_ctrl_diggain', self.u.set_digital_gain)
+        self.subscribe('db_ctrl_dcoffset', self.u.set_dc_offset_comp)
+        self.subscribe('db_ctrl_bandsel', self.u.set_band_select)
+        self.subscribe('db_ctrl_type', self.u.select_rx_antenna)
+        self.subscribe('db_test_signal', self.u.set_test_signal)
+        self['db_ctrl_bandsel'] = 'A'
+        self['cal_div_lo_freq'] = 2.1e9
+        self['cal_div_cal_freq'] = 2.102e9
+        self['db_ctrl_atten0'] = 0
+        self['db_ctrl_atten1'] = 0
+        #self['db_ctrl_10db'] = False
+        self['db_ctrl_adcgain'] = False
+        self['db_ctrl_dcoffset'] = False
+        self['db_ctrl_diggain'] = 0.0
+        self['db_ctrl_type'] = 'rf'
+        self['db_test_signal'] = vrt.VRT_TEST_SIG_NORMAL
+	self['sys_beaming'] = [16.7e6, 0, 0, 0]
+        #slider and box for freqs
+        for key, name in (('cal_div_lo_freq', 'LO Freq'), ('cal_div_cal_freq', 'Cal Freq')):
+            hbox = wx.BoxSizer(wx.HORIZONTAL)
+            hbox.AddSpacer(10)
+            forms.text_box(
+                label=name,
+                ps=self,
+                key=key,
+                sizer=hbox,
+                parent=panel,
+                proportion=0,
+                converter=forms.float_converter()
+            )
+            hbox.AddSpacer(20)
+            forms.slider(
+                ps=self,
+                key=key,
+                minimum=0,   #TODO get bounds from cal_div, from vrt...
+                maximum=int(3.5e9),
+                step_size=int(5e6),
+                cast=float,
+                sizer=hbox,
+                parent=panel,
+                proportion=2,
+            )
+            hbox.AddSpacer(10)
+            vbox.Add(hbox, 0, wx.EXPAND)
+        ############################################
+        hbox = wx.BoxSizer(wx.HORIZONTAL)
+        hbox.AddSpacer(10)
+        #create slider for atten
+        atten0_txt_box = forms.static_text(
+            label='Attenuation (0)',
+            ps=self,
+            key='db_ctrl_atten0',
+            sizer=hbox,
+            parent=panel,
+            proportion=0,
+            converter=forms.int_converter()
+        )
+        hbox.AddSpacer(20)
+        atten0_slider = forms.slider(
+            ps=self,
+            key='db_ctrl_atten0',
+            minimum=0,
+            maximum=31,
+            step_size=1,
+            cast=int,
+            sizer=hbox,
+            parent=panel,
+            proportion=2,
+        )
+        hbox.AddSpacer(10)
+        #create slider for atten
+        forms.static_text(
+            label='Attenuation (1)',
+            ps=self,
+            key='db_ctrl_atten1',
+            sizer=hbox,
+            parent=panel,
+            proportion=0,
+            converter=forms.int_converter()
+        )
+        hbox.AddSpacer(20)
+        forms.slider(
+            ps=self,
+            key='db_ctrl_atten1',
+            minimum=0,
+            maximum=31,
+            step_size=1,
+            cast=int,
+            sizer=hbox,
+            parent=panel,
+            proportion=2,
+        )
+        hbox.AddSpacer(10)
+        def update_atten0(*args):
+            for form_obj in (atten0_txt_box, atten0_slider): form_obj.Enable(self['db_ctrl_bandsel'] > 'B')
+        update_atten0()
+        self.subscribe('db_ctrl_bandsel', update_atten0)
+        #create checkbox for 10dB att
+        #forms.check_box(
+        #    label='10dB Attenuation',
+        #    ps=self,
+        #    key='db_ctrl_10db',
+        #    sizer=hbox,
+        #    parent=panel,
+        #    proportion=1,
+        #)
+        #hbox.AddSpacer(10)
+        vbox.Add(hbox, 0, wx.EXPAND)
+        hbox2 = wx.BoxSizer(wx.HORIZONTAL)
+        hbox2.AddSpacer(10)
+        forms.static_text(
+            label='ADC Controls',
+            ps=self,
+            key='db_ctrl_diggain',
+            sizer=hbox2,
+            parent=panel,
+            proportion=0,
+            converter=forms.float_converter()
+        )
+        hbox2.AddSpacer(20)
+        #create checkbox for ADC digital gain
+        forms.slider(
+            #label='ADC Digital Gain',
+            ps=self,
+            minimum=0,
+            maximum=6,
+            step_size=0.5,
+            key='db_ctrl_diggain',
+            sizer=hbox2,
+            parent=panel,
+            proportion=2,
+        )
+        hbox2.AddSpacer(10)
+        #create checkbox for 3.5dB ADC gain
+        forms.check_box(
+            label='3.5dB ADC Gain',
+            ps=self,
+            key='db_ctrl_adcgain',
+            sizer=hbox2,
+            parent=panel,
+            proportion=1,
+        )
+        hbox2.AddSpacer(10)
+        #create checkbox for DC Offset Correction in ADC
+        forms.check_box(
+            label='DC Offset Correction',
+            ps=self,
+            key='db_ctrl_dcoffset',
+            sizer=hbox2,
+            parent=panel,
+            proportion=2,
+        )
+        hbox2.AddSpacer(10)
+        vbox.Add(hbox2, 0, wx.EXPAND)
+        hbox = wx.BoxSizer(wx.HORIZONTAL)
+        hbox.AddSpacer(10)
+        #create radio buttons for band sel
+        forms.radio_buttons(
+            label='Band Select',
+            ps=self,
+            key='db_ctrl_bandsel',
+            choices=['A', 'B', 'C', 'D'],
+            labels=['A', 'B', 'C', 'D'],
+            sizer=hbox,
+            parent=panel,
+            proportion=0,
+        )
+        hbox.AddSpacer(10)
+        forms.radio_buttons(
+            label='RF Input',
+            ps=self,
+            key='db_ctrl_type',
+            choices=['rf', 'cal'],
+            labels=['Main RF', 'Calibrator'],
+            sizer=hbox,
+            parent=panel,
+            proportion=0,
+        )
+        hbox.AddSpacer(10)
+        #create radio buttons for band sel
+        types = sorted(
+            filter(lambda x: x.startswith('VRT_TEST_SIG_'), dir(vrt)),
+            lambda x, y: cmp(getattr(vrt, x), getattr(vrt, y)),
+        )
+        forms.drop_down(
+            label='Test Signal',
+            ps=self,
+            key='db_test_signal',
+            choices=map(lambda a: getattr(vrt, a), types),
+            labels=types,
+            sizer=hbox,
+            parent=panel,
+            proportion=0,
+        )
+        hbox.AddSpacer(10)
+        #create radio buttons for type
+        forms.drop_down(
+            label='Beamformer',
+            ps=self,
+            key='sys_beaming',
+            choices=[[16.7e6, 0, 0, 0], [0, 16.7e6, 0, 0], [0, 0, 16.7e6, 0], [0, 0, 0, 16.7e6], [4.19e6]*4],
+            labels=['Ant0', 'Ant1', 'Ant2', 'Ant3', 'Equal Gain'],
+            sizer=hbox,
+            parent=panel,
+            proportion=0,
+        )
+        hbox.AddSpacer(10)
+        vbox.Add(hbox, 0, wx.EXPAND)
+            
+    def set_freq(self, target_freq):
+        """
+        Set the center frequency we're interested in.
+
+        @param target_freq: frequency in Hz
+        @rypte: bool
+
+        Tuning is a two step process.  First we ask the front-end to
+        tune as close to the desired frequency as it can.  Then we use
+        the result of that operation and our target_frequency to
+        determine the value for the digital down converter.
+        """
+        return True
+    
+        r = self.u.set_center_freq(target_freq)
+        
+        if r:
+            self.myform['freq'].set_value(target_freq)     # update displayed value
+            if self.show_debug_info:
+                self.myform['baseband'].set_value(r.baseband_freq)
+                self.myform['ddc'].set_value(r.dxc_freq)
+	    if not self.options.oscilloscope:
+		self.scope.win.set_baseband_freq(target_freq)
+    	    return True
+
+        return False
+
+    def set_gain(self, gain):
+        return True
+    
+	if self.myform.has_key('gain'):
+    	    self.myform['gain'].set_value(gain)     # update displayed value
+        self.u.set_gain(gain)
+
+    def set_decim(self, decim):
+        return True
+    
+        ok = self.u.set_decim(decim)
+        if not ok:
+            print "set_decim failed"
+        #input_rate = self.u.adc_rate() / self.u.decim()
+        input_rate = 120e6/4
+        self.scope.set_sample_rate(input_rate)
+        if self.show_debug_info:  # update displayed values
+            self.myform['decim'].set_value(self.u.decim())
+            self.myform['fs@gbe'].set_value(input_rate)
+        return ok
+
+    def _setup_events(self):
+	if not self.options.waterfall and not self.options.oscilloscope:
+	    self.scope.win.Bind(wx.EVT_LEFT_DCLICK, self.evt_left_dclick)
+	    
+    def evt_left_dclick(self, event):
+	(ux, uy) = self.scope.win.GetXY(event)
+	if event.CmdDown():
+	    # Re-center on maximum power
+	    points = self.scope.win._points
+	    if self.scope.win.peak_hold:
+		if self.scope.win.peak_vals is not None:
+		    ind = numpy.argmax(self.scope.win.peak_vals)
+		else:
+		    ind = int(points.shape()[0]/2)
+	    else:
+        	ind = numpy.argmax(points[:,1])
+            (freq, pwr) = points[ind]
+	    target_freq = freq/self.scope.win._scale_factor
+	    print ind, freq, pwr
+            self.set_freq(target_freq)            
+	else:
+	    # Re-center on clicked frequency
+	    target_freq = ux/self.scope.win._scale_factor
+	    self.set_freq(target_freq)
+	    
+	
+def main ():
+    app = stdgui2.stdapp(app_top_block, "QuadRadio FFT", nstatus=1)
+    app.MainLoop()
+
+if __name__ == '__main__':
+    main ()
diff --git a/gr-vrt/Makefile.am b/gr-vrt/Makefile.am
new file mode 100644
index 000000000..96019be97
--- /dev/null
+++ b/gr-vrt/Makefile.am
@@ -0,0 +1,27 @@
+#
+# Copyright 2001,2006,2008,2009 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+# 
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+# 
+
+include $(top_srcdir)/Makefile.common
+
+SUBDIRS = src
+
+pkgconfigdir = $(libdir)/pkgconfig
+pkgconfig_DATA = gnuradio-vrt.pc
diff --git a/gr-vrt/gnuradio-vrt.pc.in b/gr-vrt/gnuradio-vrt.pc.in
new file mode 100644
index 000000000..b5f416051
--- /dev/null
+++ b/gr-vrt/gnuradio-vrt.pc.in
@@ -0,0 +1,11 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@/gnuradio
+
+Name: gnuradio-vrt
+Description: GNU Software Radio support for Virtual Radio Transport (VRT aka VITA-49)
+Requires: gnuradio-core vrt
+Version: @VERSION@
+Libs: -L${libdir} -lgnuradio-vrt
+Cflags: -I${includedir}
diff --git a/gr-vrt/src/Makefile.am b/gr-vrt/src/Makefile.am
new file mode 100644
index 000000000..671c10274
--- /dev/null
+++ b/gr-vrt/src/Makefile.am
@@ -0,0 +1,122 @@
+#
+# Copyright 2004,2005,2006,2008,2009 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+# 
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+# 
+
+include $(top_srcdir)/Makefile.common
+
+# ----------------------------------------------------------------------
+# Local Python files, not installed
+#
+# qa_vrt.py
+# ----------------------------------------------------------------------
+
+noinst_PYTHON = qa_vrt.py
+
+# ----------------------------------------------------------------------
+# Miscellaneous build operations
+# ----------------------------------------------------------------------
+
+EXTRA_DIST = run_tests.in
+TESTS = run_tests
+DISTCLEANFILES = run_tests
+
+# ----------------------------------------------------------------------
+# C++ block API interface librar(ies)
+#
+# libgnuradio_vrt.so
+# ----------------------------------------------------------------------
+AM_CPPFLAGS = \
+	$(STD_DEFINES_AND_INCLUDES)  \
+	$(GRUEL_INCLUDES) \
+	$(PYTHON_CPPFLAGS) \
+	$(VRT_INCLUDES) \
+	$(WITH_INCLUDES)
+
+lib_LTLIBRARIES = libgnuradio-vrt.la
+
+libgnuradio_vrt_la_SOURCES = \
+	missing_pkt_checker.cc \
+	vrt_source_base.cc \
+	vrt_source_32fc.cc \
+	vrt_quadradio_source_32fc.cc
+
+
+#libgnuradio_vrt_la_SOURCES = \
+#	rx_16sc_handler.cc \
+#	rx_32fc_handler.cc \
+#	vrt_base.cc \
+#	vrt_source_base.cc \
+#	vrt_source_16sc.cc \
+#	vrt_source_32fc.cc
+
+#	vrt_sink_base.cc \
+#	vrt_sink_16sc.cc \
+#	vrt_sink_32fc.cc
+
+libgnuradio_vrt_la_LIBADD = \
+	$(VRT_LA) \
+	$(GNURADIO_CORE_LA) 
+
+grinclude_HEADERS = \
+	vrt_source_base.h \
+	vrt_source_32fc.h \
+	vrt_quadradio_source_32fc.h
+
+#	vrt_source_16sc.h \
+#	vrt_sink_base.h \
+#	vrt_sink_16sc.h \
+#	vrt_sink_32fc.h
+
+noinst_HEADERS = \
+	missing_pkt_checker.h
+
+
+# ----------------------------------------------------------------------
+# Python SWIG wrapper around C++ library
+#
+# vrt.py
+# _vrt.so
+# ----------------------------------------------------------------------
+
+TOP_SWIG_IFILES =		\
+	vrt.i
+
+# Install so that they end up available as:
+#   import gnuradio.vrt
+# This ends up at:
+#   ${prefix}/lib/python${python_version}/site-packages/gnuradio
+vrt_pythondir_category =	\
+	gnuradio
+
+# additional arguments to the SWIG command
+vrt_swig_args =		\
+	$(VRT_INCLUDES)
+
+# additional libraries for linking with the SWIG-generated library
+vrt_la_swig_libadd =		\
+	libgnuradio-vrt.la
+
+include $(top_srcdir)/Makefile.swig
+
+# add some of the variables generated inside the Makefile.swig.gen
+BUILT_SOURCES = $(swig_built_sources)
+
+# Do not distribute the output of SWIG
+no_dist_files = $(swig_built_sources)
diff --git a/gr-vrt/src/Makefile.swig.gen b/gr-vrt/src/Makefile.swig.gen
new file mode 100644
index 000000000..b0a4a22fa
--- /dev/null
+++ b/gr-vrt/src/Makefile.swig.gen
@@ -0,0 +1,259 @@
+# -*- Makefile -*-
+#
+# Copyright 2009 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+# 
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+# 
+
+# Makefile.swig.gen for vrt.i
+
+## Default install locations for these files:
+##
+## Default location for the Python directory is:
+##  ${prefix}/lib/python${python_version}/site-packages/[category]/vrt
+## Default location for the Python exec directory is:
+##  ${exec_prefix}/lib/python${python_version}/site-packages/[category]/vrt
+##
+## The following can be overloaded to change the install location, but
+## this has to be done in the including Makefile.am -before-
+## Makefile.swig is included.
+
+vrt_pythondir_category ?= gnuradio/vrt
+vrt_pylibdir_category ?= $(vrt_pythondir_category)
+vrt_pythondir = $(pythondir)/$(vrt_pythondir_category)
+vrt_pylibdir = $(pyexecdir)/$(vrt_pylibdir_category)
+
+## SWIG headers are always installed into the same directory.
+
+vrt_swigincludedir = $(swigincludedir)
+
+## This is a template file for a "generated" Makefile addition (in
+## this case, "Makefile.swig.gen").  By including the top-level
+## Makefile.swig, this file will be used to generate the SWIG
+## dependencies.  Assign the variable TOP_SWIG_FILES to be the list of
+## SWIG .i files to generated wrappings for; there can be more than 1
+## so long as the names are unique (no sorting is done on the
+## TOP_SWIG_FILES list). This file explicitly assumes that a SWIG .i
+## file will generate .cc, .py, and possibly .h files -- meaning that
+## all of these files will have the same base name (that provided for
+## the SWIG .i file).
+##
+## This code is setup to ensure parallel MAKE ("-j" or "-jN") does the
+## right thing.  For more info, see <
+## http://sources.redhat.com/automake/automake.html#Multiple-Outputs >
+
+## Stamps used to ensure parallel make does the right thing.  These
+## are removed by "make clean", but otherwise unused except during the
+## parallel built.  These will not be included in a tarball, because
+## the SWIG-generated files will be removed from the distribution.
+
+STAMPS += $(DEPDIR)/vrt-generate-*
+
+## Other cleaned files: dependency files generated by SWIG or this Makefile
+
+MOSTLYCLEANFILES += $(DEPDIR)/*.S*
+
+## Add the .py and .cc files to the list of SWIG built sources.  The
+## .h file is sometimes built, but not always ... so that one has to
+## be added manually by the including Makefile.am .
+
+swig_built_sources += vrt.py vrt.cc
+
+## Various SWIG variables.  These can be overloaded in the including
+## Makefile.am by setting the variable value there, then including
+## Makefile.swig .
+
+vrt_swiginclude_HEADERS =		\
+	vrt.i			\
+	$(vrt_swiginclude_headers)
+
+vrt_pylib_LTLIBRARIES =		\
+	_vrt.la
+
+_vrt_la_SOURCES = 			\
+	vrt.cc			\
+	$(vrt_la_swig_sources)
+
+_vrt_la_LIBADD =			\
+	$(STD_SWIG_LA_LIB_ADD)		\
+	$(vrt_la_swig_libadd)
+
+_vrt_la_LDFLAGS =			\
+	$(STD_SWIG_LA_LD_FLAGS)		\
+	$(vrt_la_swig_ldflags)
+
+_vrt_la_CXXFLAGS =			\
+	$(STD_SWIG_CXX_FLAGS)		\
+	$(vrt_la_swig_cxxflags)
+
+vrt_python_PYTHON =			\
+	vrt.py			\
+	$(vrt_python)
+
+## Entry rule for running SWIG
+
+vrt.h vrt.py vrt.cc: vrt.i
+## This rule will get called only when MAKE decides that one of the
+## targets needs to be created or re-created, because:
+##
+## * The .i file is newer than any or all of the generated files;
+##
+## * Any or all of the .cc, .h, or .py files does not exist and is
+##   needed (in the case this file is not needed, the rule for it is
+##   ignored); or
+##
+## * Some SWIG-based dependecy of the .cc file isn't met and hence the
+##   .cc file needs be be regenerated.  Explanation: Because MAKE
+##   knows how to handle dependencies for .cc files (regardless of
+##   their name or extension), then the .cc file is used as a target
+##   instead of the .i file -- but with the dependencies of the .i
+##   file.  It is this last reason why the line:
+##
+##     	if test -f $@; then :; else
+##
+##   cannot be used in this case: If a .i file dependecy is not met,
+##   then the .cc file needs to be rebuilt.  But if the stamp is newer
+##   than the .cc file, and the .cc file exists, then in the original
+##   version (with the 'test' above) the internal MAKE call will not
+##   be issued and hence the .cc file will not be rebuilt.
+##
+## Once execution gets to here, it should always proceed no matter the
+## state of a stamp (as discussed in link above).  The
+## $(DEPDIR)/vrt-generate stuff is used to allow for parallel
+## builds to "do the right thing".  The stamp has no relationship with
+## either the target files or dependency file; it is used solely for
+## the protection of multiple builds during a given call to MAKE.
+##
+## Catch signals SIGHUP (1), SIGINT (2), SIGPIPE (13), and SIGTERM
+## (15).  At a caught signal, the quoted command will be issued before
+## exiting.  In this case, remove any stamp, whether temporary of not.
+## The trap is valid until the process exits; the process includes all
+## commands appended via "\"s.
+##
+	trap 'rm -rf $(DEPDIR)/vrt-generate-*' 1 2 13 15; \
+##
+## Create a temporary directory, which acts as a lock.  The first
+## process to create the directory will succeed and issue the MAKE
+## command to do the actual work, while all subsequent processes will
+## fail -- leading them to wait for the first process to finish.
+##
+	if mkdir $(DEPDIR)/vrt-generate-lock 2>/dev/null; then \
+##
+## This code is being executed by the first process to succeed in
+## creating the directory lock.
+##
+## Remove the stamp associated with this filename.
+##
+		rm -f $(DEPDIR)/vrt-generate-stamp; \
+##
+## Tell MAKE to run the rule for creating this stamp.
+##
+		$(MAKE) $(AM_MAKEFLAGS) $(DEPDIR)/vrt-generate-stamp WHAT=$<; \
+##
+## Now that the .cc, .h, and .py files have been (re)created from the
+## .i file, future checking of this rule during the same MAKE
+## execution will come back that the rule doesn't need to be executed
+## because none of the conditions mentioned at the start of this rule
+## will be positive.  Remove the the directory lock, which frees up
+## any waiting process(es) to continue.
+##
+		rmdir $(DEPDIR)/vrt-generate-lock; \
+	else \
+##
+## This code is being executed by any follower processes while the
+## directory lock is in place.
+##
+## Wait until the first process is done, testing once per second.
+##
+		while test -d $(DEPDIR)/vrt-generate-lock; do \
+			sleep 1; \
+		done; \
+##
+## Succeed if and only if the first process succeeded; exit this
+## process returning the status of the generated stamp.
+##
+		test -f $(DEPDIR)/vrt-generate-stamp; \
+		exit $$?; \
+	fi;
+
+$(DEPDIR)/vrt-generate-stamp:
+## This rule will be called only by the first process issuing the
+## above rule to succeed in creating the lock directory, after
+## removing the actual stamp file in order to guarantee that MAKE will
+## execute this rule.
+##
+## Call SWIG to generate the various output files; special
+## post-processing on 'mingw32' host OS for the dependency file.
+##
+	if $(SWIG) $(STD_SWIG_PYTHON_ARGS) $(vrt_swig_args) \
+		-MD -MF $(DEPDIR)/vrt.Std \
+		-module vrt -o vrt.cc $(WHAT); then \
+	    if test $(host_os) = mingw32; then \
+		$(RM) $(DEPDIR)/vrt.Sd; \
+		$(SED) 's,\\\\,/,g' < $(DEPDIR)/vrt.Std \
+			> $(DEPDIR)/vrt.Sd; \
+		$(RM) $(DEPDIR)/vrt.Std; \
+		$(MV) $(DEPDIR)/vrt.Sd $(DEPDIR)/vrt.Std; \
+	    fi; \
+	else \
+	    $(RM) $(DEPDIR)/vrt.S*; exit 1; \
+	fi;
+##
+## Mess with the SWIG output .Std dependency file, to create a
+## dependecy file valid for the input .i file: Basically, simulate the
+## dependency file created for libraries by GNU's libtool for C++,
+## where all of the dependencies for the target are first listed, then
+## each individual dependency is listed as a target with no further
+## dependencies.
+##
+## (1) remove the current dependency file
+##
+	$(RM) $(DEPDIR)/vrt.d
+##
+## (2) Copy the whole SWIG file:
+##
+	cp $(DEPDIR)/vrt.Std $(DEPDIR)/vrt.d
+##
+## (3) all a carriage return to the end of the dependency file.
+##
+	echo "" >> $(DEPDIR)/vrt.d
+##
+## (4) from the SWIG file, remove the first line (the target); remove
+##     trailing " \" and " " from each line.  Append ":" to each line,
+##     followed by 2 carriage returns, then append this to the end of
+##     the dependency file.
+##
+	$(SED) -e '1d;s, \\,,g;s, ,,g' < $(DEPDIR)/vrt.Std | \
+		awk '{ printf "%s:\n\n", $$0 }' >> $(DEPDIR)/vrt.d
+##
+## (5) remove the SWIG-generated file
+##
+	$(RM) $(DEPDIR)/vrt.Std
+##
+## Create the stamp for this filename generation, to signal success in
+## executing this rule; allows other threads waiting on this process
+## to continue.
+##
+	touch $(DEPDIR)/vrt-generate-stamp
+
+# KLUDGE: Force runtime include of a SWIG dependency file.  This is
+# not guaranteed to be portable, but will probably work.  If it works,
+# we have accurate dependencies for our swig stuff, which is good.
+
+@am__include@ @am__quote@./$(DEPDIR)/vrt.d@am__quote@
+
diff --git a/gr-vrt/src/missing_pkt_checker.cc b/gr-vrt/src/missing_pkt_checker.cc
new file mode 100644
index 000000000..09b70fe2c
--- /dev/null
+++ b/gr-vrt/src/missing_pkt_checker.cc
@@ -0,0 +1,47 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <missing_pkt_checker.h>
+
+int
+missing_pkt_checker::check(const vrt::expanded_header *hdr)
+{
+  // FIXME assumes we're inspecting only a single stream
+
+  int nmissing = 0;
+  int actual = hdr->pkt_cnt();
+  int expected = (d_last_pkt_cnt + 1) & 0xf;
+  if (actual != expected && !d_resync){
+    d_nwrong_pkt_cnt++;
+    if (actual > expected)
+      nmissing = actual - expected;
+    else
+      nmissing = actual + 16 - expected;
+    d_nmissing_pkt_est += nmissing;
+  }
+  d_last_pkt_cnt = actual;
+  d_npackets++;
+  d_resync = false;
+  return nmissing;
+}
diff --git a/gr-vrt/src/missing_pkt_checker.h b/gr-vrt/src/missing_pkt_checker.h
new file mode 100644
index 000000000..ab171ffa3
--- /dev/null
+++ b/gr-vrt/src/missing_pkt_checker.h
@@ -0,0 +1,57 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef INCLUDED_MISSING_PKT_CHECKER_H
+#define INCLUDED_MISSING_PKT_CHECKER_H
+
+#include <vrt/expanded_header.h>
+#include <stdint.h>
+
+/*!
+ * \brief Check for missing packets
+ */
+class missing_pkt_checker
+{
+  // FIXME assumes we're inspecting only a single stream
+
+  bool		d_resync;
+  uint64_t	d_npackets;		//< total number of packets
+  int		d_last_pkt_cnt;		//< the last pkt_cnt we saw
+  uint64_t	d_nwrong_pkt_cnt; 	//< number of incorrect pkt_cnt
+  uint64_t	d_nmissing_pkt_est;    	//< estimate of total number of missing pkts
+  
+public:
+  missing_pkt_checker()
+    : d_resync(true), d_npackets(0), d_last_pkt_cnt(0xf), d_nwrong_pkt_cnt(0),
+      d_nmissing_pkt_est(0) {}
+    
+  /*!
+   * \brief check header pkt_cnt and return 0 if OK, else estimate of number of missing packets.
+   */
+  int check(const vrt::expanded_header *hdr);
+
+  void resync() { d_resync = true; }
+  uint64_t npackets() const { return d_npackets; }
+  uint64_t nwrong_pkt_cnt() const { return d_nwrong_pkt_cnt; }
+  uint64_t nmissing_pkt_est() const { return d_nmissing_pkt_est; }
+};
+
+
+#endif /* INCLUDED_MISSING_PKT_CHECKER_H */
diff --git a/gr-vrt/src/qa_vrt.py b/gr-vrt/src/qa_vrt.py
new file mode 100755
index 000000000..9df1edd92
--- /dev/null
+++ b/gr-vrt/src/qa_vrt.py
@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+#
+# Copyright 2005,2008,2009 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+# 
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+# 
+
+from gnuradio import gr, gr_unittest
+import vrt
+
+class qa_vrt(gr_unittest.TestCase):
+
+    def setUp(self):
+        self.tb = gr.top_block()
+
+    def tearDown(self):
+        self.tb = None
+
+    def test_000_nop (self):
+        """Just see if we can import the module...
+        They may not have a VRT connected, etc.  Don't try to run anything"""
+        pass
+    
+if __name__ == '__main__':
+    gr_unittest.main ()
diff --git a/gr-vrt/src/run_tests.in b/gr-vrt/src/run_tests.in
new file mode 100644
index 000000000..5c56c4674
--- /dev/null
+++ b/gr-vrt/src/run_tests.in
@@ -0,0 +1,17 @@
+#!/bin/sh
+
+# 1st parameter is absolute path to component source directory
+# 2nd parameter is absolute path to component build directory
+# 3rd parameter is path to Python QA directory
+
+# For OS/X
+DYLD_LIBRARY_PATH=@abs_top_builddir@/vrt/host/lib/legacy:@abs_top_builddir@/vrt/host/lib/legacy/.libs:$DYLD_LIBRARY_PATH
+export DYLD_LIBRARY_PATH
+
+# For Win32
+PATH=@abs_top_builddir@/vrt/host/lib/legacy:@abs_top_builddir@/vrt/host/lib/legacy/.libs:$PATH
+
+@top_builddir@/run_tests.sh \
+    @abs_top_srcdir@/gr-vrt \
+    @abs_top_builddir@/gr-vrt \
+    @srcdir@
diff --git a/gr-vrt/src/vrt.i b/gr-vrt/src/vrt.i
new file mode 100644
index 000000000..9016dc33e
--- /dev/null
+++ b/gr-vrt/src/vrt.i
@@ -0,0 +1,64 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008,2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+%include "gnuradio.i"	// the common stuff
+%import <stdint.i>
+
+%{
+#include "vrt_quadradio_source_32fc.h"
+#include <vrt/quadradio.h>
+//#include "vrt_quadradio_source_16sc.h"
+//#include "vrt_sink_32fc.h"
+//#include "vrt_sink_16sc.h"
+%}
+
+%template(uint32_t_vector) std::vector<uint32_t>;
+
+// ----------------------------------------------------------------
+
+class vrt_source_base : public gr_sync_block
+{
+protected:
+  vrt_source_base() throw (std::runtime_error);
+
+public:
+  ~vrt_source_base();
+
+};
+
+class vrt_source_32fc : public vrt_source_base
+{
+protected:
+  vrt_source_32fc() throw (std::runtime_error);
+
+public:
+  ~vrt_source_32fc();
+  void reset();
+};
+
+// ----------------------------------------------------------------
+
+GR_SWIG_BLOCK_MAGIC(vrt,quadradio_source_32fc)
+
+%include "vrt_quadradio_source_32fc.h"
+
+%include <vrt/quadradio.h>
diff --git a/gr-vrt/src/vrt_quadradio_source_32fc.cc b/gr-vrt/src/vrt_quadradio_source_32fc.cc
new file mode 100644
index 000000000..0321062aa
--- /dev/null
+++ b/gr-vrt/src/vrt_quadradio_source_32fc.cc
@@ -0,0 +1,212 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <vrt_quadradio_source_32fc.h>
+#include <vrt/quadradio.h>
+#include <vrt/rx_packet_handler.h>
+#include <cstdio>
+
+vrt_quadradio_source_32fc_sptr
+vrt_make_quadradio_source_32fc(const std::string &ip, 
+			       size_t rx_bufsize,
+			       size_t samples_per_pkt)
+{
+  return gnuradio::get_initial_sptr(new vrt_quadradio_source_32fc(ip,
+								  rx_bufsize,
+								  samples_per_pkt));
+}
+
+vrt_quadradio_source_32fc::vrt_quadradio_source_32fc(const std::string &ip,
+						     size_t rx_bufsize,
+						     size_t samples_per_pkt)
+  : vrt_source_32fc("quadradio_source_32fc"),
+    d_samples_per_pkt(samples_per_pkt == 0 ? 800 : samples_per_pkt),
+    d_qr(vrt::quadradio::sptr(new vrt::quadradio(ip, rx_bufsize)))
+{
+}
+
+vrt_quadradio_source_32fc::~vrt_quadradio_source_32fc()
+{
+  d_qr->stop_streaming();
+}
+
+vrt::rx::sptr 
+vrt_quadradio_source_32fc::vrt_rx() const
+{
+  return d_qr->vrt_rx();
+}
+
+bool 
+vrt_quadradio_source_32fc::start()
+{
+  // throw away any stale packets before starting
+  vrt::rx_packet_handler nop;
+  vrt_rx()->rx_packets(&nop, true);
+  d_checker.resync();
+
+  return d_qr->start_streaming(d_samples_per_pkt);
+}  
+
+bool
+vrt_quadradio_source_32fc::stop()
+{
+  return d_qr->stop_streaming();
+}
+
+bool 
+vrt_quadradio_source_32fc::set_dboard_pins(int which_dboard, int v)
+{
+  return d_qr->set_dboard_pins(which_dboard, v);
+}
+
+bool 
+vrt_quadradio_source_32fc::set_center_freq(double target_freq)
+{
+  return d_qr->set_center_freq(target_freq);
+}
+
+bool 
+vrt_quadradio_source_32fc::set_band_select(const std::string &band)
+{
+  return d_qr->set_band_select(band);
+}
+
+//void 
+//vrt_quadradio_source_32fc::set_10dB_atten(bool on)
+//{
+//  return d_qr->set_10dB_atten(on);
+//}
+
+bool 
+vrt_quadradio_source_32fc::select_rx_antenna(const std::string &ant)
+{
+  return d_qr->select_rx_antenna(ant);
+}
+
+bool 
+vrt_quadradio_source_32fc::set_attenuation0(int attenuation)
+{
+  return d_qr->set_attenuation0(attenuation);
+}
+
+bool 
+vrt_quadradio_source_32fc::set_attenuation1(int attenuation)
+{
+  return d_qr->set_attenuation1(attenuation);
+}
+
+void
+vrt_quadradio_source_32fc::set_adc_gain(bool on){
+  d_qr->set_adc_gain(on);
+}
+
+void
+vrt_quadradio_source_32fc::set_dc_offset_comp(bool on){
+  d_qr->set_dc_offset_comp(on);
+}
+
+void
+vrt_quadradio_source_32fc::set_digital_gain(float gain){
+  d_qr->set_digital_gain(gain);
+}
+
+void
+vrt_quadradio_source_32fc::set_test_signal(int type){
+  d_qr->set_test_signal(static_cast<vrt_test_sig_t>(type));
+}
+
+bool
+vrt_quadradio_source_32fc::set_setting_reg(int regno, int value)
+{
+  return d_qr->set_setting_reg(regno, value);
+}
+
+bool
+vrt_quadradio_source_32fc::set_hsadc_conf(int which_dboard, int regno, int value)
+{
+  return d_qr->set_hsadc_conf(which_dboard, regno, value);
+}
+
+bool
+vrt_quadradio_source_32fc::set_lsdac(int which_dboard, int which_dac, int value)
+{
+  return d_qr->set_lsdac(which_dboard, which_dac, value);
+}
+
+bool
+vrt_quadradio_source_32fc::set_mem32(int addr, int value)
+{
+  return d_qr->set_mem32(addr, value);
+}
+
+bool
+vrt_quadradio_source_32fc::set_lo_freq(double freq)
+{
+  return d_qr->set_lo_freq(freq);
+}
+
+bool
+vrt_quadradio_source_32fc::set_cal_freq(double freq)
+{
+  return d_qr->set_cal_freq(freq);
+}
+
+/*--------------------------------------------------------------------*/
+#define IQ_IMBAL_NUM_TAPS 30
+#define IQ_IMBAL_REG_NO 162
+
+//helper function to set the iq imbalance register with a tap
+static int get_iq_imbal_reg(bool real, bool init, float tap){
+  int val = int(round(tap));
+  val &= 0x1ffffff; //lower 25 bits for tap
+  val |= (real?0:1) << 30; //30th bit for filter type
+  val |= (init?1:0) << 31; //31st bit for initialization
+  printf("Reg %d Val %x\n", IQ_IMBAL_REG_NO, val);
+  return val;
+}
+
+void
+vrt_quadradio_source_32fc::set_iq_imbal_taps(const std::vector<gr_complex> taps){
+  int i = 0;
+  /* set the real part of the taps */
+  get_iq_imbal_reg(true, true, 0);
+  for (i = 0; i < IQ_IMBAL_NUM_TAPS; i++){
+      set_setting_reg(IQ_IMBAL_REG_NO, get_iq_imbal_reg(true, false, taps[IQ_IMBAL_NUM_TAPS-i-1].real()));
+  }
+  get_iq_imbal_reg(false, true, 0);
+  /* set the imaginary part of the taps */
+  for (i = 0; i < IQ_IMBAL_NUM_TAPS; i++){
+      set_setting_reg(IQ_IMBAL_REG_NO, get_iq_imbal_reg(false, false, taps[IQ_IMBAL_NUM_TAPS-i-1].imag()));
+  }
+}
+
+bool
+vrt_quadradio_source_32fc::set_beamforming(std::vector<gr_complex> gains){
+  int32_t gains_ints[8];
+  for (int i = 0; i < 4; i++){
+    gains_ints[2*i] = int32_t(gains[i].real());
+    gains_ints[2*i+1] = int32_t(gains[i].imag());
+  }
+ return d_qr->set_beamforming(gains_ints);
+}
+
diff --git a/gr-vrt/src/vrt_quadradio_source_32fc.h b/gr-vrt/src/vrt_quadradio_source_32fc.h
new file mode 100644
index 000000000..6ad63f7be
--- /dev/null
+++ b/gr-vrt/src/vrt_quadradio_source_32fc.h
@@ -0,0 +1,116 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef INCLUDED_VRT_QUADRADIO_SOURCE_32FC_H
+#define INCLUDED_VRT_QUADRADIO_SOURCE_32FC_H
+
+#include <vrt_source_32fc.h>
+
+namespace vrt {
+  class quadradio;
+};
+
+class vrt_quadradio_source_32fc;
+typedef boost::shared_ptr<vrt_quadradio_source_32fc> vrt_quadradio_source_32fc_sptr;
+
+vrt_quadradio_source_32fc_sptr
+vrt_make_quadradio_source_32fc(const std::string &ip,
+			       size_t rx_bufsize = 0,
+			       size_t samples_per_pkt = 0);
+
+class vrt_quadradio_source_32fc : public vrt_source_32fc
+{
+  size_t				d_samples_per_pkt;
+  boost::shared_ptr<vrt::quadradio>	d_qr;
+
+  vrt_quadradio_source_32fc(const std::string &ip, size_t rx_bufsize,
+			    size_t samples_per_pkt);
+
+  friend vrt_quadradio_source_32fc_sptr
+  vrt_make_quadradio_source_32fc(const std::string &ip, size_t rx_bufsize,
+				 size_t samples_per_pkt);
+
+public:
+  virtual ~vrt_quadradio_source_32fc();
+  virtual vrt::rx::sptr vrt_rx() const;
+
+  /*!
+   * \brief Called by scheduler when starting flowgraph
+   */
+  virtual bool start();
+  
+  /*!
+   * \brief Called by scheduler when stopping flowgraph
+   */
+  virtual bool stop();
+
+  /*!
+   * \brief Set the LO frequency (actually just sets the band select for now).
+   */
+  bool set_center_freq(double target_freq);
+
+  /*!
+   * \brief Set the band select dboard bits.
+   * \param band "A", "B", "C", "D"
+   */
+  bool set_band_select(const std::string &band);
+
+  /*!
+   * \brief Turn the 10 dB attenuation on/off.
+   */
+  //void set_10dB_atten(bool on);
+
+  /*!
+   * \brief Set the antenna type to the main rf or calibrator.
+   * \param ant "rf" or "cal"
+   */
+  bool select_rx_antenna(const std::string &ant);
+
+  /*!
+   * \brief Set the attenuation.
+   * \param attenuation 0 to 31 in dB
+   */
+  bool set_attenuation0(int attenuation);
+  bool set_attenuation1(int attenuation);
+
+  void set_iq_imbal_taps(const std::vector<gr_complex> taps);
+
+  void set_adc_gain(bool on);
+  void set_dc_offset_comp(bool on);
+  void set_digital_gain(float gain);
+  void set_test_signal(int type);
+
+  bool set_setting_reg(int regno, int value);
+
+  /*!
+   * \brief write \p v to daugherboard control setting register
+   */
+  bool set_dboard_pins(int which_dboard, int v);
+  bool set_hsadc_conf(int which_dboard, int regno, int value);
+  bool set_lsdac(int which_dboard, int which_dac, int value);
+  bool set_mem32(int addr, int value);
+  bool set_lo_freq(double freq);
+  bool set_cal_freq(double freq);
+  bool set_beamforming(std::vector<gr_complex> gains);
+};
+
+
+
+#endif /* INCLUDED_VRT_QUADRADIO_SOURCE_32FC_H */
diff --git a/gr-vrt/src/vrt_sink_16sc.cc b/gr-vrt/src/vrt_sink_16sc.cc
new file mode 100644
index 000000000..09abe29ee
--- /dev/null
+++ b/gr-vrt/src/vrt_sink_16sc.cc
@@ -0,0 +1,73 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <vrt_sink_16sc.h>
+#include <vrt/metadata.h>
+#include <gr_io_signature.h>
+#include <iostream>
+
+vrt_sink_16sc_sptr
+vrt_make_sink_16sc(const std::string &ifc, const std::string &mac_addr) 
+  throw (std::runtime_error)
+{
+  return gnuradio::get_initial_sptr(new vrt_sink_16sc(ifc, mac_addr));
+}
+
+vrt_sink_16sc::vrt_sink_16sc(const std::string &ifc, const std::string &mac_addr) 
+  throw (std::runtime_error)
+  : vrt_sink_base("vrt_sink_16sc",
+		    gr_make_io_signature(1, 1, sizeof(std::complex<int16_t>)),
+		    ifc, mac_addr)
+{
+  // NOP
+}
+
+vrt_sink_16sc::~vrt_sink_16sc()
+{
+  // NOP
+}
+
+int
+vrt_sink_16sc::work(int noutput_items,
+		      gr_vector_const_void_star &input_items,
+		      gr_vector_void_star &output_items)
+{
+  std::complex<int16_t> *in = (std::complex<int16_t> *)input_items[0];
+
+  vrt::tx_metadata metadata;
+  metadata.timestamp = -1;
+  metadata.send_now = 1;
+  metadata.start_of_burst = 1;
+
+  bool ok = d_u2->tx_16sc(0,  // FIXME: someday, streams will have channel numbers
+			  in, noutput_items, &metadata);
+  if (!ok){
+    std::cerr << "vrt_sink_16sc: tx_16sc failed" << std::endl;
+    return -1;	// say we're done
+  }
+
+  return noutput_items;
+}
diff --git a/gr-vrt/src/vrt_sink_16sc.h b/gr-vrt/src/vrt_sink_16sc.h
new file mode 100644
index 000000000..ba6e673be
--- /dev/null
+++ b/gr-vrt/src/vrt_sink_16sc.h
@@ -0,0 +1,56 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef INCLUDED_USRP2_SINK_16SC_H
+#define INCLUDED_USRP2_SINK_16SC_H
+
+#include <vrt_sink_base.h>
+
+class vrt_sink_16sc;
+typedef boost::shared_ptr<vrt_sink_16sc> vrt_sink_16sc_sptr;
+
+vrt_sink_16sc_sptr
+vrt_make_sink_16sc(const std::string &ifc="eth0",
+		     const std::string &mac="")
+  throw (std::runtime_error);
+
+class vrt_sink_16sc : public vrt_sink_base 
+{
+private:
+  friend vrt_sink_16sc_sptr
+  vrt_make_sink_16sc(const std::string &ifc,
+		       const std::string &mac) 
+    throw (std::runtime_error);
+  
+protected:
+  vrt_sink_16sc(const std::string &ifc, const std::string &mac) 
+    throw (std::runtime_error);
+
+public:
+  ~vrt_sink_16sc();
+
+  int work(int noutput_items,
+	   gr_vector_const_void_star &input_items,
+	   gr_vector_void_star &output_items);
+};
+
+#endif /* INCLUDED_USRP2_SINK_16SC_H */
diff --git a/gr-vrt/src/vrt_sink_32fc.cc b/gr-vrt/src/vrt_sink_32fc.cc
new file mode 100644
index 000000000..a9987a361
--- /dev/null
+++ b/gr-vrt/src/vrt_sink_32fc.cc
@@ -0,0 +1,73 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <vrt_sink_32fc.h>
+#include <vrt/metadata.h>
+#include <gr_io_signature.h>
+#include <iostream>
+
+vrt_sink_32fc_sptr
+vrt_make_sink_32fc(const std::string &ifc, const std::string &mac_addr) 
+  throw (std::runtime_error)
+{
+  return gnuradio::get_initial_sptr(new vrt_sink_32fc(ifc, mac_addr));
+}
+
+vrt_sink_32fc::vrt_sink_32fc(const std::string &ifc, const std::string &mac_addr) 
+  throw (std::runtime_error)
+  : vrt_sink_base("vrt_sink_32fc",
+		    gr_make_io_signature(1, 1, sizeof(gr_complex)),
+		    ifc, mac_addr)
+{
+  // NOP
+}
+
+vrt_sink_32fc::~vrt_sink_32fc()
+{
+  // NOP
+}
+
+int
+vrt_sink_32fc::work(int noutput_items,
+		      gr_vector_const_void_star &input_items,
+		      gr_vector_void_star &output_items)
+{
+  gr_complex *in = (gr_complex *)input_items[0];
+
+  vrt::tx_metadata metadata;
+  metadata.timestamp = -1;
+  metadata.send_now = 1;
+  metadata.start_of_burst = 1;
+
+  bool ok = d_u2->tx_32fc(0, // FIXME: someday, streams will have channel numbers
+			  in, noutput_items, &metadata);
+  if (!ok){
+    std::cerr << "vrt_sink_32fc: tx_32fc failed" << std::endl;
+    return -1;	// say we're done
+  }
+
+  return noutput_items;
+}
diff --git a/gr-vrt/src/vrt_sink_32fc.h b/gr-vrt/src/vrt_sink_32fc.h
new file mode 100644
index 000000000..55a6512f0
--- /dev/null
+++ b/gr-vrt/src/vrt_sink_32fc.h
@@ -0,0 +1,56 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef INCLUDED_USRP2_SINK_32FC_H
+#define INCLUDED_USRP2_SINK_32FC_H
+
+#include <vrt_sink_base.h>
+
+class vrt_sink_32fc;
+typedef boost::shared_ptr<vrt_sink_32fc> vrt_sink_32fc_sptr;
+
+vrt_sink_32fc_sptr
+vrt_make_sink_32fc(const std::string &ifc="eth0",
+		     const std::string &mac="")
+  throw (std::runtime_error);
+
+class vrt_sink_32fc : public vrt_sink_base 
+{
+private:
+  friend vrt_sink_32fc_sptr
+  vrt_make_sink_32fc(const std::string &ifc,
+		       const std::string &mac) 
+    throw (std::runtime_error);
+  
+protected:
+  vrt_sink_32fc(const std::string &ifc, const std::string &mac) 
+    throw (std::runtime_error);
+
+public:
+  ~vrt_sink_32fc();
+
+  int work(int noutput_items,
+	   gr_vector_const_void_star &input_items,
+	   gr_vector_void_star &output_items);
+};
+
+#endif /* INCLUDED_USRP2_SINK_32FC_H */
diff --git a/gr-vrt/src/vrt_sink_base.cc b/gr-vrt/src/vrt_sink_base.cc
new file mode 100644
index 000000000..a75024dcc
--- /dev/null
+++ b/gr-vrt/src/vrt_sink_base.cc
@@ -0,0 +1,151 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <vrt_sink_base.h>
+#include <gr_io_signature.h>
+#include <iostream>
+
+vrt_sink_base::vrt_sink_base(const char *name,
+				 gr_io_signature_sptr input_signature,
+				 const std::string &ifc,
+				 const std::string &mac) 
+  throw (std::runtime_error)
+  : vrt_base(name,
+               input_signature,
+	       gr_make_io_signature(0, 0, 0),
+	       ifc, mac)
+{
+  // NOP
+}
+
+vrt_sink_base::~vrt_sink_base ()
+{
+  // NOP
+}
+
+bool
+vrt_sink_base::set_gain(double gain)
+{
+  return d_u2->set_tx_gain(gain);
+}
+
+bool
+vrt_sink_base::set_lo_offset(double frequency)
+{
+  return d_u2->set_tx_lo_offset(frequency);
+}
+
+bool
+vrt_sink_base::set_center_freq(double frequency, vrt::tune_result *tr)
+{
+  return d_u2->set_tx_center_freq(frequency, tr);
+}
+
+bool
+vrt_sink_base::set_interp(int interp_factor)
+{
+  return d_u2->set_tx_interp(interp_factor);
+}
+
+void
+vrt_sink_base::default_scale_iq(int interp_factor, int *scale_i, int *scale_q)
+{
+  return d_u2->default_tx_scale_iq(interp_factor, scale_i, scale_q);
+}
+
+bool 
+vrt_sink_base::set_scale_iq(int scale_i, int scale_q)
+{
+  return d_u2->set_tx_scale_iq(scale_i, scale_q);
+}
+
+int
+vrt_sink_base::interp()
+{
+  return d_u2->tx_interp();
+}
+
+bool
+vrt_sink_base::dac_rate(long *rate)
+{
+  return d_u2->dac_rate(rate);
+}
+
+double
+vrt_sink_base::gain_min()
+{
+  return d_u2->tx_gain_min();
+}
+
+double
+vrt_sink_base::gain_max()
+{
+  return d_u2->tx_gain_max();
+}
+
+double
+vrt_sink_base::gain_db_per_step()
+{
+  return d_u2->tx_gain_db_per_step();
+}
+  
+double
+vrt_sink_base::freq_min()
+{
+  return d_u2->tx_freq_min();
+}
+
+double
+vrt_sink_base::freq_max()
+{
+  return d_u2->tx_freq_max();
+}
+
+bool
+vrt_sink_base::daughterboard_id(int *dbid)
+{
+  return d_u2->tx_daughterboard_id(dbid);
+}
+
+bool vrt_sink_base::set_gpio_ddr(uint16_t value, uint16_t mask)
+{
+  return d_u2->set_gpio_ddr(vrt::GPIO_TX_BANK, value, mask);
+}
+
+bool vrt_sink_base::set_gpio_sels(std::string sels)
+{
+  return d_u2->set_gpio_sels(vrt::GPIO_TX_BANK, sels);
+}
+
+bool vrt_sink_base::write_gpio(uint16_t value, uint16_t mask)
+{
+  return d_u2->write_gpio(vrt::GPIO_TX_BANK, value, mask);
+}
+
+bool vrt_sink_base::read_gpio(uint16_t *value)
+{
+  return d_u2->read_gpio(vrt::GPIO_TX_BANK, value);
+}
diff --git a/gr-vrt/src/vrt_sink_base.h b/gr-vrt/src/vrt_sink_base.h
new file mode 100644
index 000000000..5f0532d8e
--- /dev/null
+++ b/gr-vrt/src/vrt_sink_base.h
@@ -0,0 +1,139 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef INCLUDED_USRP2_SINK_BASE_H
+#define INCLUDED_USRP2_SINK_BASE_H
+
+#include <vrt_base.h>
+
+/*!
+ * Base class for all USRP2 transmit blocks
+ */
+class vrt_sink_base : public vrt_base 
+{
+protected:
+  vrt_sink_base(const char *name,
+		  gr_io_signature_sptr input_signature,
+		  const std::string &ifc,
+		  const std::string &mac)
+    throw (std::runtime_error);
+
+public:
+  ~vrt_sink_base();
+
+  /*!
+   * \brief Set transmitter gain
+   */
+  bool set_gain(double gain);
+
+  /*!
+   * \brief Set transmitter LO offset frequency
+   */
+  bool set_lo_offset(double frequency);
+
+  /*!
+   * \brief Set transmitter center frequency
+   */
+  bool set_center_freq(double frequency, vrt::tune_result *tr);
+   
+  /*!
+   * \brief Set transmit interpolation rate
+   */
+  bool set_interp(int interp_factor);
+
+  /*!
+   * \brief Calculate default scale_iq for given interpolation factor
+   */
+  void default_scale_iq(int interpolation_factor, int *scale_i, int *scale_q);
+
+  /*!
+   * \brief Set transmit IQ scale factors
+   */
+  bool set_scale_iq(int scale_i, int scale_q);
+
+  /*!
+   * \brief Get transmit interpolation rate
+   */
+  int interp();
+
+  /*!
+   * \brief Get DAC sample rate in Hz 
+   */
+  bool dac_rate(long *rate);
+
+  /*!
+   * \brief Returns minimum Tx gain 
+   */
+  double gain_min();
+
+  /*!
+   * \brief Returns maximum Tx gain 
+   */
+  double gain_max();
+  
+  /*!
+   * \brief Returns Tx gain db_per_step
+   */
+  double gain_db_per_step();
+
+  /*!
+   * \brief Returns minimum Tx center frequency
+   */
+  double freq_min();
+
+  /*!
+   * \brief Returns maximum Tx center frequency
+   */
+  double freq_max();
+
+  /*!
+   * \brief Get Tx daughterboard ID
+   *
+   * \param[out] dbid returns the daughterboard id.
+   *
+   * daughterboard id >= 0 if successful, -1 if no daugherboard installed,
+   * -2 if invalid EEPROM on daughterboard.
+   */
+  bool daughterboard_id(int *dbid);
+
+  /*!
+   * \brief Set daughterboard GPIO data direction register.
+   */
+  bool set_gpio_ddr(uint16_t value, uint16_t mask);
+
+  /*!
+   * \brief Set daughterboard GPIO output selection register.
+   */
+  bool set_gpio_sels(std::string sels);
+
+  /*!
+   * \brief Set daughterboard GPIO pin values.
+   */
+  bool write_gpio(uint16_t value, uint16_t mask);
+
+  /*!
+   * \brief Read daughterboard GPIO pin values
+   */
+  bool read_gpio(uint16_t *value);
+};
+
+#endif /* INCLUDED_USRP2_SINK_BASE_H */
diff --git a/gr-vrt/src/vrt_source_16sc.cc b/gr-vrt/src/vrt_source_16sc.cc
new file mode 100644
index 000000000..f0ea35bb3
--- /dev/null
+++ b/gr-vrt/src/vrt_source_16sc.cc
@@ -0,0 +1,69 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <vrt_source_16sc.h>
+#include <rx_16sc_handler.h>
+#include <gr_io_signature.h>
+#include <iostream>
+
+vrt_source_16sc_sptr
+vrt_make_source_16sc(const std::string &ifc, const std::string &mac_addr) 
+  throw (std::runtime_error)
+{
+  return gnuradio::get_initial_sptr(new vrt_source_16sc(ifc, mac_addr));
+}
+
+vrt_source_16sc::vrt_source_16sc(const std::string &ifc, const std::string &mac_addr) 
+  throw (std::runtime_error)
+  : vrt_source_base("vrt_source_16sc",
+		      gr_make_io_signature(1, 1, sizeof(std::complex<int16_t>)),
+		      ifc, mac_addr)
+{
+  set_output_multiple(USRP2_MIN_RX_SAMPLES);
+}
+
+vrt_source_16sc::~vrt_source_16sc()
+{
+  // NOP
+}
+
+int
+vrt_source_16sc::work(int noutput_items,
+			gr_vector_const_void_star &input_items,
+			gr_vector_void_star &output_items)
+{
+  std::complex<int16_t> *out = (std::complex<int16_t> *)output_items[0];
+
+  rx_16sc_handler::sptr handler = rx_16sc_handler::make(noutput_items, USRP2_MIN_RX_SAMPLES, out);
+
+  bool ok = d_u2->rx_samples(0, handler.get()); // FIXME: channel number instead of 0
+  if (!ok){
+    std::cerr << "vrt::rx_samples() failed" << std::endl;
+    return -1;	// say we're done
+  }
+
+  return handler->nsamples();
+}
diff --git a/gr-vrt/src/vrt_source_16sc.h b/gr-vrt/src/vrt_source_16sc.h
new file mode 100644
index 000000000..34175b3ca
--- /dev/null
+++ b/gr-vrt/src/vrt_source_16sc.h
@@ -0,0 +1,54 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef INCLUDED_USRP2_SOURCE_16SC_H
+#define INCLUDED_USRP2_SOURCE_16SC_H
+
+#include <vrt_source_base.h>
+
+class vrt_source_16sc;
+typedef boost::shared_ptr<vrt_source_16sc> vrt_source_16sc_sptr;
+
+vrt_source_16sc_sptr
+vrt_make_source_16sc(const std::string &ifc="eth0",
+		       const std::string &mac="")
+  throw (std::runtime_error);
+
+class vrt_source_16sc : public vrt_source_base
+{
+private:
+  friend vrt_source_16sc_sptr
+  vrt_make_source_16sc(const std::string &ifc,
+			 const std::string &mac) throw (std::runtime_error);
+  
+protected:
+  vrt_source_16sc(const std::string &ifc, const std::string &mac) throw (std::runtime_error);
+
+public:
+  ~vrt_source_16sc();
+
+  int work(int noutput_items,
+	   gr_vector_const_void_star &input_items,
+	   gr_vector_void_star &output_items);
+};
+
+#endif /* INCLUDED_USRP2_SOURCE_16SC_H */
diff --git a/gr-vrt/src/vrt_source_32fc.cc b/gr-vrt/src/vrt_source_32fc.cc
new file mode 100644
index 000000000..beb5ef26d
--- /dev/null
+++ b/gr-vrt/src/vrt_source_32fc.cc
@@ -0,0 +1,144 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008,2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <vrt_source_32fc.h>
+#include <vrt/expanded_header.h>
+#include <vrt/copiers.h>
+#include <gr_io_signature.h>
+#include <missing_pkt_checker.h>
+#include <iostream>
+
+#define VERBOSE 1		// define to 0 or 1
+
+
+class rx_32fc_handler : public vrt::rx_packet_handler
+{
+  int 			 	      d_noutput_items;
+  std::complex<float>		     *d_out;
+  int				     *d_oo;		// output index
+  std::vector< std::complex<float> > &d_remainder;
+  missing_pkt_checker		     &d_checker;
+  
+
+public:
+
+  rx_32fc_handler(int noutput_items, std::complex<float> *out,
+		  int *oo, std::vector< std::complex<float> > &remainder,
+		  missing_pkt_checker &checker)
+    : d_noutput_items(noutput_items), d_out(out),
+      d_oo(oo), d_remainder(remainder), d_checker(checker) {}
+
+  ~rx_32fc_handler();
+
+  bool operator()(const uint32_t *payload,
+		  size_t n32_bit_words,
+		  const vrt::expanded_header *hdr);
+};
+
+rx_32fc_handler::~rx_32fc_handler()
+{
+}
+
+bool
+rx_32fc_handler::operator()(const uint32_t *payload,
+			    size_t n32_bit_words,
+			    const vrt::expanded_header *hdr)
+{
+  int nmissing = d_checker.check(hdr);
+  if (VERBOSE && nmissing != 0){
+    std::cerr << "S" << nmissing;
+  }
+
+  // copy as many as will fit into the output buffer.
+
+  size_t n = std::min(n32_bit_words, (size_t)(d_noutput_items - *d_oo));
+  vrt::copy_net_16sc_to_host_32fc(n, payload, &d_out[*d_oo]);
+  *d_oo += n;
+
+  // if there are any left over, copy them into remainder and tell
+  // our caller we're had enough for now.
+
+  size_t r = n32_bit_words - n;
+  if (r > 0){
+    assert(d_remainder.size() == 0);
+    d_remainder.resize(r);
+    vrt::copy_net_16sc_to_host_32fc(r, &payload[n], &d_remainder[0]);
+    return false;		// Stop calling us.
+  }
+
+  return true;			// Keep calling us, we've got more room
+}
+
+
+// ------------------------------------------------------------------------
+
+vrt_source_32fc::vrt_source_32fc(const char *name)
+
+  : vrt_source_base(name,
+		    gr_make_io_signature(1, 1, sizeof(gr_complex)))
+{
+}
+
+vrt_source_32fc::~vrt_source_32fc()
+{
+  if (VERBOSE){
+    std::cerr << "\nvrt_source_32fc: npackets = " << d_checker.npackets()
+	      << " nwrong_pkt_cnt = " << d_checker.nwrong_pkt_cnt()
+	      << " nmissing_pkt_est = " << d_checker.nmissing_pkt_est()
+	      << std::endl;
+  }
+}
+
+int
+vrt_source_32fc::work(int noutput_items,
+		      gr_vector_const_void_star &input_items,
+		      gr_vector_void_star &output_items)
+{
+  gr_complex *out = (gr_complex *)output_items[0];
+  int	oo = 0;
+
+  // Handle any samples left over from the last call.
+  int t = std::min(noutput_items, (int)d_remainder.size());
+  if (t != 0){
+    for (int i = 0; i < t; i++)
+      out[i] = d_remainder[i];
+    d_remainder.erase(d_remainder.begin(), d_remainder.begin()+t);
+    oo = t;
+  }
+  if (noutput_items - oo == 0)
+    return oo;
+  
+  // While we've got room, and there are packets, handle them
+  rx_32fc_handler h(noutput_items, out, &oo, d_remainder, d_checker);
+  bool ok = vrt_rx()->rx_packets(&h);
+
+  if (!ok){
+    std::cerr << "vrt_source_32fc: vrt::rx_packets() failed" << std::endl;
+    return -1;	// say we're done
+  }
+
+  return oo;
+}
diff --git a/gr-vrt/src/vrt_source_32fc.h b/gr-vrt/src/vrt_source_32fc.h
new file mode 100644
index 000000000..7ca3e5fe2
--- /dev/null
+++ b/gr-vrt/src/vrt_source_32fc.h
@@ -0,0 +1,48 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008,2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef INCLUDED_VRT_SOURCE_32FC_H
+#define INCLUDED_VRT_SOURCE_32FC_H
+
+#include <vrt_source_base.h>
+#include <missing_pkt_checker.h>
+
+class vrt_source_32fc : public vrt_source_base
+{
+protected:
+  vrt_source_32fc(const char *name);
+
+  std::vector< std::complex<float> >	d_remainder;
+  missing_pkt_checker			d_checker;
+
+public:
+  ~vrt_source_32fc();
+
+  int work(int noutput_items,
+	   gr_vector_const_void_star &input_items,
+	   gr_vector_void_star &output_items);
+
+  void reset() { d_remainder.clear(); }
+
+};
+
+#endif /* INCLUDED_VRT_SOURCE_32FC_H */
diff --git a/gr-vrt/src/vrt_source_base.cc b/gr-vrt/src/vrt_source_base.cc
new file mode 100644
index 000000000..40e871653
--- /dev/null
+++ b/gr-vrt/src/vrt_source_base.cc
@@ -0,0 +1,41 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008,2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <vrt_source_base.h>
+#include <gr_io_signature.h>
+#include <iostream>
+
+vrt_source_base::vrt_source_base(const char *name,
+				 gr_io_signature_sptr output_signature)
+  : gr_sync_block(name,
+		  gr_make_io_signature(0, 0, 0),
+		  output_signature)
+{
+}
+
+vrt_source_base::~vrt_source_base()
+{
+}
diff --git a/gr-vrt/src/vrt_source_base.h b/gr-vrt/src/vrt_source_base.h
new file mode 100644
index 000000000..e67778860
--- /dev/null
+++ b/gr-vrt/src/vrt_source_base.h
@@ -0,0 +1,45 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008,2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef INCLUDED_VRT_SOURCE_BASE_H
+#define INCLUDED_VRT_SOURCE_BASE_H
+
+#include <gr_sync_block.h>
+#include <vrt/rx.h>
+#include <gr_io_signature.h>
+
+/*!
+ * Base class for all VRT source blocks
+ */
+class vrt_source_base : public gr_sync_block
+{
+protected:
+  vrt_source_base(const char *name,
+		  gr_io_signature_sptr output_signature);
+
+public:
+  ~vrt_source_base();
+
+  virtual vrt::rx::sptr vrt_rx() const = 0;
+};
+
+#endif /* INCLUDED_VRT_SOURCE_BASE_H */
diff --git a/vrt/Makefile.am b/vrt/Makefile.am
new file mode 100644
index 000000000..791b8d65c
--- /dev/null
+++ b/vrt/Makefile.am
@@ -0,0 +1,29 @@
+#
+# Copyright 2008,2009 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+# 
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+
+include $(top_srcdir)/Makefile.common
+
+pkgconfigdir = $(libdir)/pkgconfig
+pkgconfig_DATA = vrt.pc
+
+EXTRA_DIST = \
+	vrt.pc.in        
+
+SUBDIRS = include lib apps
diff --git a/vrt/apps/Makefile.am b/vrt/apps/Makefile.am
new file mode 100644
index 000000000..631d9020b
--- /dev/null
+++ b/vrt/apps/Makefile.am
@@ -0,0 +1,36 @@
+#
+# Copyright 2009 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+include $(top_srcdir)/Makefile.common
+
+AM_CPPFLAGS = \
+    $(VRT_INCLUDES) \
+    $(STD_DEFINES_AND_INCLUDES) \
+    $(CPPUNIT_INCLUDES)
+
+LDADD = \
+	$(VRT_LA) \
+	$(GRUEL_LA)
+
+
+bin_PROGRAMS = 
+
+noinst_PROGRAMS = \
+	simple_rx_samples
+
+simple_rx_samples_SOURCES = simple_rx_samples.cc
+
diff --git a/vrt/apps/simple_rx_samples.cc b/vrt/apps/simple_rx_samples.cc
new file mode 100644
index 000000000..6b09afda5
--- /dev/null
+++ b/vrt/apps/simple_rx_samples.cc
@@ -0,0 +1,394 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <vrt/quadradio.h>
+#include <vrt/rx.h>
+#include <vrt/copiers.h>
+
+#include <errno.h>
+#include <iostream>
+#include <boost/scoped_ptr.hpp>
+#include <boost/shared_ptr.hpp>
+#include <stdexcept>
+#include <signal.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <gruel/realtime.h>
+#include <complex>
+
+#define	MIN_IP_LOCAL_PORT	32768
+#define	MAX_IP_LOCAL_PORT	61000
+
+static volatile bool signaled = false;
+
+static void 
+sig_handler(int sig)
+{
+  signaled = true;
+}
+
+static void
+install_sig_handler(int signum,
+		    void (*new_handler)(int))
+{
+  struct sigaction new_action;
+  memset (&new_action, 0, sizeof (new_action));
+
+  new_action.sa_handler = new_handler;
+  sigemptyset (&new_action.sa_mask);
+  new_action.sa_flags = 0;
+
+  if (sigaction (signum, &new_action, 0) < 0){
+    perror ("sigaction (install new)");
+    throw std::runtime_error ("sigaction");
+  }
+}
+
+// ------------------------------------------------------------------------
+
+class rx_nop_handler : public vrt::rx_packet_handler
+{
+private:
+  uint64_t	d_max_samples;
+  uint64_t	d_max_quantum;
+  uint64_t	d_nsamples;
+  uint64_t	d_npackets;
+  int		d_last_pkt_cnt;
+  uint64_t	d_nwrong_pkt_cnt;
+
+protected:
+  bool		d_err;
+
+public:
+
+  // Shared pointer to an instance of this class
+  typedef boost::shared_ptr<rx_nop_handler> sptr;
+
+  /*!
+   * Constructor
+   *
+   * \param max_samples  Maximum number of samples to copy. Use zero for no maximum.
+   * \param max_quantum  Maximum number of samples required to accept in one call.
+   *                     Use 0 to indicate no maximum.
+   */
+  rx_nop_handler(uint64_t max_samples, uint64_t max_quantum=0)
+    : d_max_samples(max_samples), d_max_quantum(max_quantum),
+      d_nsamples(0), d_npackets(0), 
+      d_last_pkt_cnt(0xf), d_nwrong_pkt_cnt(0),
+      d_err(false){}
+
+    
+    ~rx_nop_handler();
+  
+  bool operator()(const uint32_t *payload,
+		  size_t n32_bit_words,
+		  const vrt::expanded_header *hdr);
+
+  /*!
+   * \brief Returns number of packets this copier was called with
+   */
+  uint64_t npackets() const { return d_npackets; }
+
+  /*!
+   * \brief Returns actual number of samples copied
+   */
+  uint64_t nsamples() const { return d_nsamples; }
+
+  /*!
+   * \brief Returns maximum number of samples that will be copied
+   */
+  uint64_t max_samples() const { return d_max_samples; }
+
+  /*!
+   * Returns true if an error has occurred. Derived classes must set d_err to true
+   * when an error occurs in the () operator
+   */
+  bool has_errored_p() const { return d_err; }
+
+  /*!
+   * \brief Returns true if this instance has reached the maximum number of samples
+   */
+  bool has_finished_p() const 
+  { return d_max_samples == 0 ? false : d_nsamples >= d_max_samples-d_max_quantum; }
+      
+  uint64_t nwrong_pkt_cnt() const { return d_nwrong_pkt_cnt; }
+
+
+};
+
+
+rx_nop_handler::~rx_nop_handler()
+{
+}
+
+bool
+rx_nop_handler::operator()(const uint32_t *payload,
+			   size_t n32_bit_words,
+			   const vrt::expanded_header *hdr)
+{
+  if (d_npackets != 0 && hdr->pkt_cnt() != ((d_last_pkt_cnt + 1) & 0xf)){
+    d_nwrong_pkt_cnt++;
+    fprintf(stderr, "bad cnt (pkt %lld)\n", d_npackets);
+  }
+  d_last_pkt_cnt = hdr->pkt_cnt();
+
+  d_nsamples += n32_bit_words;
+  d_npackets++;
+
+  return !has_finished_p();
+}
+
+// ------------------------------------------------------------------------
+
+class file_writer_16sc : public rx_nop_handler
+{
+  FILE	       *d_fp;
+  std::string	d_filename;
+  
+public:
+
+  file_writer_16sc(const std::string &filename, uint64_t max_samples)
+    : rx_nop_handler(max_samples), d_filename(filename)
+  {
+    d_fp = fopen(filename.c_str(), "wb");
+    if (d_fp == 0){
+      perror(filename.c_str());
+      throw std::invalid_argument(filename);
+    }
+  }
+
+  ~file_writer_16sc();
+
+  bool 
+  operator()(const uint32_t *items, size_t nitems, const vrt::expanded_header *hdr)
+  {
+    bool ok = rx_nop_handler::operator()(items, nitems, hdr);
+
+    size_t host_nitems = nitems;
+    std::complex<int16_t> host_items[host_nitems];
+
+    vrt::copy_net_16sc_to_host_16sc(nitems, items, host_items);
+
+    size_t n = 0;
+    while (n < host_nitems){
+      size_t r = fwrite(&host_items[n], sizeof(host_items[0]), host_nitems - n, d_fp);
+      n += r;
+      if (r == 0){	// out of space?
+        d_err = true;
+	perror(d_filename.c_str());
+	ok = false;
+	break;
+      }
+    }
+
+    return ok;
+  }
+};
+
+file_writer_16sc::~file_writer_16sc()
+{
+  fclose(d_fp);
+}
+
+// ------------------------------------------------------------------------
+
+class file_writer_32fc : public rx_nop_handler
+{
+  FILE	       *d_fp;
+  std::string	d_filename;
+  
+public:
+
+  file_writer_32fc(const std::string &filename, uint64_t max_samples)
+    : rx_nop_handler(max_samples), d_filename(filename)
+  {
+    d_fp = fopen(filename.c_str(), "wb");
+    if (d_fp == 0){
+      perror(filename.c_str());
+      throw std::invalid_argument(filename);
+    }
+  }
+
+  ~file_writer_32fc();
+
+  bool 
+  operator()(const uint32_t *items, size_t nitems, const vrt::expanded_header *hdr)
+  {
+    bool ok = rx_nop_handler::operator()(items, nitems, hdr);
+
+    size_t host_nitems = nitems;
+    std::complex<float> host_items[host_nitems];
+
+    vrt::copy_net_16sc_to_host_32fc(nitems, items, host_items);
+
+    size_t n = 0;
+    while (n < host_nitems){
+      size_t r = fwrite(&host_items[n], sizeof(host_items[0]), host_nitems - n, d_fp);
+      n += r;
+      if (r == 0){	// out of space?
+        d_err = true;
+	perror(d_filename.c_str());
+	ok = false;
+	break;
+      }
+    }
+
+    return ok;
+  }
+};
+
+file_writer_32fc::~file_writer_32fc()
+{
+  fclose(d_fp);
+}
+
+// ------------------------------------------------------------------------
+
+static void
+usage(const char *progname)
+{
+  const char *p = strrchr(progname, '/');	// drop leading directory path
+  if (p)
+    p++;
+
+  if (strncmp(p, "lt-", 3) == 0)		// drop lt- libtool prefix
+    p += 3;
+  
+  fprintf(stderr, "Usage: %s [options]\n\n", p);
+  fprintf(stderr, "Options:\n");
+  fprintf(stderr, "  -h                   show this message and exit\n");
+//fprintf(stderr, "  -e ETH_INTERFACE     specify ethernet interface [default=eth0]\n");
+//fprintf(stderr, "  -m MAC_ADDR          mac address of USRP2 HH:HH [default=first one found]\n");
+//fprintf(stderr, "  -f FREQUENCY         specify receive center frequency in Hz [default=0.0]\n");
+//fprintf(stderr, "  -d DECIM             specify receive decimation rate [default=5]\n");
+//fprintf(stderr, "  -g GAIN              specify receive daughterboard gain [default=0]\n");
+  fprintf(stderr, "  -N NSAMPLES          specify number of samples to receive [default=infinite]\n");
+  fprintf(stderr, "  -o OUTPUT_FILENAME   specify file to receive samples [default=none]\n");
+  fprintf(stderr, "  -s                   write complex<short> [default=complex<float>]\n");
+  fprintf(stderr, "  -S samples_per_pkt   specify # of samples per pkt [default=maximum]\n");
+//fprintf(stderr, "  -v                   verbose output\n");
+}
+
+
+int
+main(int argc, char **argv)
+{
+  const char *quad_radio_ip = "192.168.123.123";
+  size_t rx_bufsize = 62.5e6;	    // sizeof memory mapped network buffer
+  int samples_per_pkt = 0;	    // use default
+  uint64_t nsamples = 0;
+  char *output_filename = 0;
+  bool output_shorts = false;
+  int t;
+
+  int ch;
+
+  while ((ch = getopt(argc, argv, "hN:o:sS:")) != EOF){
+    switch (ch){
+    case 'N':
+      nsamples = (uint64_t) strtod(optarg, 0);
+      break;
+
+    case 'o':
+      output_filename = optarg;
+      break;
+
+    case 's':
+      output_shorts = true;
+      break;
+
+    case 'S':
+      errno = 0;
+      t = strtol(optarg, 0, 0);
+      if (errno != 0){
+	usage(argv[0]);
+	exit(1);
+      }
+      samples_per_pkt = t;
+      break;
+
+    case 'h':
+    default:
+      usage(argv[0]);
+      exit(1);
+    }
+  }
+
+
+  install_sig_handler(SIGINT, sig_handler);
+
+  gruel::rt_status_t rt = gruel::enable_realtime_scheduling();
+  if (rt != gruel::RT_OK)
+    std::cerr << "Failed to enable realtime scheduling" << std::endl;
+
+    
+  vrt::quadradio::sptr qr;
+  try {
+    qr = vrt::quadradio::sptr(new vrt::quadradio(quad_radio_ip, rx_bufsize));
+  }
+  catch (...){
+    std::cerr << "Failed to create vrt::quadradio\n";
+    return 1;
+  }
+
+
+  rx_nop_handler::sptr handler;
+  if (output_filename){
+    if (output_shorts)
+      handler = rx_nop_handler::sptr(new file_writer_16sc(output_filename, nsamples));
+    else
+      handler = rx_nop_handler::sptr(new file_writer_32fc(output_filename, nsamples));
+  }
+  else
+    handler = rx_nop_handler::sptr(new rx_nop_handler(nsamples));
+
+
+  printf("samples_per_pkt = %d\n", samples_per_pkt);
+
+  if (!qr->start_streaming(samples_per_pkt)){
+    fprintf(stderr, "failed to send_rx_command\n");
+    return 1;
+  }
+
+  // start receiving packets
+
+  while(1
+	&& !signaled
+	&& !handler->has_errored_p()
+	&& !handler->has_finished_p()){
+    bool ok = qr->vrt_rx()->rx_packets(handler.get());
+    if (!ok){
+      fprintf(stderr, "vrt->rx_packets failed\n");
+      break;
+    }
+  }
+
+  qr->stop_streaming();
+
+  printf("%llu packets received, %llu bad pkt_cnt field values, %llu samples\n",
+	 handler->npackets(), handler->nwrong_pkt_cnt(), handler->nsamples());
+
+  //sleep(1);
+
+  return 0;
+}
diff --git a/vrt/include/Makefile.am b/vrt/include/Makefile.am
new file mode 100644
index 000000000..3ce6a8f32
--- /dev/null
+++ b/vrt/include/Makefile.am
@@ -0,0 +1,23 @@
+#
+# Copyright 2009 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+# 
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+
+include $(top_srcdir)/Makefile.common
+
+SUBDIRS = vrt
diff --git a/vrt/include/vrt/Makefile.am b/vrt/include/vrt/Makefile.am
new file mode 100644
index 000000000..b710547d9
--- /dev/null
+++ b/vrt/include/vrt/Makefile.am
@@ -0,0 +1,30 @@
+#
+# Copyright 2008,2009 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+include $(top_srcdir)/Makefile.common
+
+INCLUDES = 
+
+vrtincludedir = $(includedir)/vrt
+
+vrtinclude_HEADERS = \
+	bits.h \
+	copiers.h \
+	expanded_header.h \
+	quadradio.h \
+	rx.h \
+	rx_packet_handler.h
diff --git a/vrt/include/vrt/bits.h b/vrt/include/vrt/bits.h
new file mode 100644
index 000000000..bb4227db4
--- /dev/null
+++ b/vrt/include/vrt/bits.h
@@ -0,0 +1,72 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef INCLUDED_VRT_BITS_H
+#define INCLUDED_VRT_BITS_H
+
+#include <stdint.h>
+
+
+/* VRT Header bits */
+
+#define	VRTH_PT_MASK		  (0xf << 28)
+#define	VRTH_PT_IF_DATA_NO_SID	  (0x0 << 28)	// IF-Data, no stream id
+#define	VRTH_PT_IF_DATA_WITH_SID  (0x1 << 28)	// IF-Data, w/ stream id
+#define VRTH_PT_EXT_DATA_NO_SID	  (0x2 << 28)
+#define	VRTH_PT_EXT_DATA_WITH_SID (0x3 << 28)
+#define	VRTH_PT_IF_CONTEXT	  (0x4 << 28)
+#define	VRTH_PT_EXT_CONTEXT	  (0x5 << 28)
+
+#define	VRTH_HAS_CLASSID	  (1 << 27)
+#define	VRTH_HAS_TRAILER	  (1 << 26)	// Data pkts only
+#define	VRTH_START_OF_BURST	  (1 << 25)	// Data (Tx) pkts only
+#define	VRTH_END_OF_BURST	  (1 << 24)	// Data (Tx) pkts only
+#define	VRTH_TSM		  (1 << 24)	// Context pkts only
+
+#define	VRTH_TSI_MASK		  (0x3 << 22)
+#define	VRTH_TSI_NONE		  (0x0 << 22)
+#define	VRTH_TSI_UTC		  (0x1 << 22)
+#define	VRTH_TSI_GPS		  (0x2 << 22)
+#define VRTH_TSI_OTHER		  (0x3 << 22)
+
+#define	VRTH_TSF_MASK		  (0x3 << 20)
+#define	VRTH_TSF_NONE		  (0x0 << 20)
+#define	VRTH_TSF_SAMPLE_CNT	  (0x1 << 20)
+#define	VRTH_TSF_REAL_TIME_PS	  (0x2 << 20)
+#define	VRTH_TSF_FREE_RUNNING	  (0x3 << 20)
+
+#define	VRTH_PKT_CNT_MASK	  (0xf << 16)
+#define	VRTH_PKT_SIZE_MASK	  0xffff		    
+
+
+static inline int
+vrth_pkt_cnt(uint32_t h)
+{
+  return (h & VRTH_PKT_CNT_MASK) >> 16;
+}
+
+static inline int
+vrth_pkt_size(uint32_t h)
+{
+  return h & VRTH_PKT_SIZE_MASK;
+}
+
+#endif /* INCLUDED_VRT_BITS_H */
diff --git a/vrt/include/vrt/copiers.h b/vrt/include/vrt/copiers.h
new file mode 100644
index 000000000..990538c42
--- /dev/null
+++ b/vrt/include/vrt/copiers.h
@@ -0,0 +1,49 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef INCLUDED_VRT_COPIERS_H
+#define INCLUDED_VRT_COPIERS_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include <complex>
+
+namespace vrt {
+
+  /*!
+   * \brief Copy and convert from net format to host format
+   */
+  void 
+  copy_net_16sc_to_host_16sc(size_t nitems,
+			     const uint32_t *items,
+			     std::complex<int16_t> *host_items);
+
+
+  /*!
+   * \brief Copy and convert from net format to host format mapping [-32768, 32767] -> [1.0, +1.0)
+   */
+  void
+  copy_net_16sc_to_host_32fc(size_t nitems,
+			     const uint32_t *items,
+			     std::complex<float> *host_items);
+};
+
+#endif /* INCLUDED_VRT_COPIERS_H */
diff --git a/vrt/include/vrt/expanded_header.h b/vrt/include/vrt/expanded_header.h
new file mode 100644
index 000000000..0cfca04a1
--- /dev/null
+++ b/vrt/include/vrt/expanded_header.h
@@ -0,0 +1,99 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef INCLUDED_VRT_EXPANDED_HEADER_H
+#define INCLUDED_VRT_EXPANDED_HEADER_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include <vrt/bits.h>
+
+namespace vrt {
+
+  /*!
+   * \brief All headers and trailer for VRT IF-Data, Extension-Data,
+   * IF-Context and Extension-Context packets.
+   *
+   * There are fields allocated for each possible header.  Their content may
+   * or may not be valid.  Check the header field to confirm their validity.
+   * All values are in host-endian format.
+   */
+  struct expanded_header {
+    uint32_t	header;			// first word of all packets
+    uint32_t	stream_id;		// optional stream identifier
+    uint64_t	class_id;		// optional class identifier
+    uint32_t	integer_secs;		// optional integer seconds timestamp
+    uint64_t	fractional_secs;	// optional fractional seconds timestamp
+    uint32_t	trailer;		// optional trailer (only possible in data pkts)
+
+    expanded_header()
+      : header(0) /*, stream_id(0), class_id(0),
+        integer_secs(0), fractional_secs(0), trailer(0)*/ {}
+
+
+    int pkt_type() const {
+      return (header & VRTH_PT_MASK) >> 28;
+    }
+    
+    int pkt_cnt() const { return vrth_pkt_cnt(header); }
+    size_t pkt_size() const { return vrth_pkt_size(header); }
+
+
+    // packet type predicates
+    bool if_data_p() const { return s_if_data[pkt_type()]; }
+    bool ext_data_p() const { return s_ext_data[pkt_type()]; }
+    bool if_context_p() const { return (header & VRTH_PT_MASK) == VRTH_PT_IF_CONTEXT; }
+    bool ext_context_p() const { return (header & VRTH_PT_MASK) == VRTH_PT_EXT_CONTEXT; }
+
+    bool data_p() const { return s_data[pkt_type()]; }	// if_data_p() || ext_data_p()
+    bool context_p() const { return s_context[pkt_type()]; }	// if_context_p() || ext_context_p()
+
+    // optional info predicates
+    bool stream_id_p() const { return s_stream_id[pkt_type()]; }
+    bool class_id_p() const { return (header & VRTH_HAS_CLASSID) != 0; }
+    bool integer_secs_p() const { return (header & VRTH_TSI_MASK) != 0; }
+    bool fractional_secs_p() const { return (header & VRTH_TSF_MASK) != 0; }
+    bool trailer_p() const { return (header & VRTH_HAS_TRAILER) != 0 && data_p(); }
+
+
+    // parser
+
+    /*!
+     * \brief parse packet, fill-in expanded header, start of payload and len of payload
+     */
+    static bool parse(const uint32_t *packet,		// in
+		      size_t n32_bit_words_packet,	// in
+		      expanded_header *hdr,		// out
+		      const uint32_t **payload,		// out
+		      size_t *n32_bit_words_payload);	// out
+		      
+  private:
+    static unsigned char s_if_data[16];
+    static unsigned char s_ext_data[16];
+    static unsigned char s_data[16];
+    static unsigned char s_context[16];
+    static unsigned char s_stream_id[16];
+
+  };
+
+}; // vrt
+
+
+#endif /* INCLUDED_VRT_EXPANDED_HEADER_H */
diff --git a/vrt/include/vrt/quadradio.h b/vrt/include/vrt/quadradio.h
new file mode 100644
index 000000000..747ca8ef4
--- /dev/null
+++ b/vrt/include/vrt/quadradio.h
@@ -0,0 +1,129 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef INCLUDED_VRT_QUADRADIO_H
+#define INCLUDED_VRT_QUADRADIO_H
+
+#include <vrt/rx.h>
+
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+typedef enum{
+    VRT_TEST_SIG_NORMAL=0,
+    VRT_TEST_SIG_ZEROS=1,
+    VRT_TEST_SIG_ONES=2,
+    VRT_TEST_SIG_TOGGLE=3,
+    VRT_TEST_SIG_RAMP=4,
+    VRT_TEST_SIG_CUSTOM=5,  
+      
+    } vrt_test_sig_t;
+
+namespace vrt {
+
+  /*
+   * We're not committing to this interface.  It's just here so we can make progress...
+   *
+   * This implements the ad-hoc control for bringup and has-a vrt::rx
+   */
+  class quadradio
+  {
+    int		   d_ctrl_fd;	       // socket for control
+    struct in_addr d_ctrl_port_inaddr; // our ip addr
+    int		   d_data_fd;	       // socket for data (owned by d_rx)
+    int		   d_data_port;	       // our data port number
+    vrt::rx::sptr  d_rx;	       // has-a rx
+    
+    int		   d_band_select;	       // band select setting
+    int		   d_rx_antenna;	       // antenna type rf/cal
+    int		   d_attenuation0;	       // attenuation setting
+    int		   d_attenuation1;	       // attenuation setting
+    bool	   d_10dB_atten;	       // 10dB attenuation on/of
+
+    static bool
+    open_sockets(const char *quad_radio_ip, int quad_radio_ctrl_port,
+		 int *ctrl_fd_ptr, struct in_addr *ctrl_port_inaddr,
+		 int *data_fd_ptr, int *data_port_ptr);
+
+    static bool
+    send_rx_command(int ctrl_fd, bool start,
+		    struct in_addr addr, int data_port, int samples_per_pkt, int siggen_param);
+
+    static bool
+    send_stop_rx_command(int ctrl_fd);
+    
+    static int control_port() { return 790; }
+    int data_socket_fd() const { return d_data_fd; }
+
+    bool open(const char *ip);
+    
+    void update_dboard_pins(void);
+
+  public:
+    typedef boost::shared_ptr<quadradio> sptr;
+
+    quadradio(const std::string &ip, size_t rx_bufsize = 0);
+    ~quadradio();
+
+    vrt::rx::sptr vrt_rx() const { return d_rx; }
+
+    bool start_streaming(int samples_per_pkt = 0);
+    bool stop_streaming();
+
+
+    /* convenience methods that ultimately write the dboard pins */
+    bool set_center_freq(double target_freq);
+    bool set_band_select(const std::string &band);
+    //void set_10dB_atten(bool on);
+    bool set_attenuation0(int attenuation);
+    bool select_rx_antenna(const std::string &ant);
+    bool set_attenuation1(int attenuation);
+    
+    /* convenience methods that ultimately call set_hsadc_conf */
+    void set_adc_gain(bool on);
+    void set_dc_offset_comp(bool on);
+    void set_digital_gain(float gain);
+    void set_test_signal(vrt_test_sig_t type);
+    
+    /* primitives */
+    bool set_setting_reg(int regno, int value);
+    bool set_mem32(int addr, int value);	// poke a 32-bit value
+    bool set_lo_freq(double freq);
+    bool set_cal_freq(double freq);
+    bool set_beamforming(int32_t gains[8]);
+    /*
+     * The first parameter for these is a bitmask which indicates which
+     * daughterboard or daughterboards to apply the operation to.
+     * 0x1	-> dboard 0
+     * 0x2	-> dboard 1
+     * 0x3	-> dboard 0 and 1...
+     */
+    bool set_dboard_pins(int dboard_bitmask, int v);
+    bool set_hsadc_conf(int dboard_bitmask, int regno, int value);
+    bool set_lsdac(int dboard_bitmask, int which_dac, int value);
+
+  };
+
+};
+
+
+#endif /* INCLUDED_QUADRADIO_H */
diff --git a/vrt/include/vrt/rx.h b/vrt/include/vrt/rx.h
new file mode 100644
index 000000000..ff3ce85fb
--- /dev/null
+++ b/vrt/include/vrt/rx.h
@@ -0,0 +1,93 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef INCLUDED_VRT_RX_H
+#define INCLUDED_VRT_RX_H
+
+#include <boost/shared_ptr.hpp>
+#include <boost/utility.hpp>
+#include <vrt/rx_packet_handler.h>
+
+namespace vrt {
+
+  class socket_rx_buffer;
+
+  /*!
+   * Relatively low-level interface to receive VRT packets over a datagram socket.
+   *
+   * (We'll refactor this if/when we use a non-UDP transport.)
+   * No VRT control issues are addressed here.
+   */
+  class rx : boost::noncopyable
+  {
+    int			d_socket_fd;
+    socket_rx_buffer   *d_srb;
+
+  public:
+    /*!
+     * Shared pointer to this class
+     */ 
+    typedef boost::shared_ptr<rx> sptr;
+
+    /*! 
+     * \brief Static function to return an instance of rx as a shared pointer.
+     *
+     * \param socket_fd file descriptor that data grams will be received from.
+     *	                It is assumed that some higher-level control software
+     *	                opened the appropriate UDP socket for us.  This object
+     *	                assumes management of the socket's lifetime.  The
+     *	                socket will be closed when our destructor fires.
+     *
+     * \param rx_bufsize is a hint as to the number of bytes of memory
+     * 			to allocate for received ethernet frames (0 -> reasonable default)
+     */
+    static sptr make(int socket_fd, size_t rx_bufsize = 0);
+
+    /*! 
+     * \param socket_fd file descriptor that data grams will be received from.
+     *	                It is assumed that some higher-level control software
+     *	                opened the appropriate UDP socket for us.  This object
+     *	                assumes management of the socket's lifetime.  The
+     *	                socket will be closed when our destructor fires.
+     *
+     * \param rx_bufsize is a hint as to the number of bytes of memory
+     * 			to allocate for received ethernet frames (0 -> reasonable default)
+     */
+    rx(int socket_fd, size_t rx_bufsize = 0);
+    ~rx();
+
+    /*!
+     * \brief Receive packets from the given socket file descriptor.
+     *
+     * \p handler will be invoked for all available packets.
+     * Unless \p dont_wait is true, this function blocks until at
+     * least one packet has been processed.
+     */
+    bool rx_packets(rx_packet_handler *handler, bool dont_wait = false);
+
+    /*
+     * \returns the socket_fd.   Useful for select or poll.
+     */
+    int socket_fd() const { return d_socket_fd; }
+  };
+
+}
+
+#endif /* INCLUDED_VRT_RX_H */
diff --git a/vrt/include/vrt/rx_packet_handler.h b/vrt/include/vrt/rx_packet_handler.h
new file mode 100644
index 000000000..ad3407813
--- /dev/null
+++ b/vrt/include/vrt/rx_packet_handler.h
@@ -0,0 +1,62 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef INCLUDED_VRT_RX_PACKET_HANDLER_H
+#define INCLUDED_VRT_RX_PACKET_HANDLER_H
+
+#include <vrt/expanded_header.h>
+#include <stddef.h>
+
+namespace vrt {
+
+  /*!
+   * \brief Abstract function object called to handle received VRT packets.
+   *
+   * An object derived from this class is passed to vrt_rx_udp::rx_packets
+   * to process the received packets.
+   */
+  class rx_packet_handler {
+  public:
+    virtual ~rx_packet_handler();
+
+    /*!
+     * \param payload points to the first 32-bit word of the payload field.
+     * \param n32_bit_words is the number of 32-bit words in the payload field.
+     * \param hdr is the expanded version of the mandatory and optional header fields (& trailer).
+     *
+     * \p payload points to the raw payload section of the packet received off
+     * the wire. The data is network-endian (aka big-endian) 32-bit integers.
+     *
+     * This is the general purpose, low level interface and relies on other
+     * functions to handle all required endian-swapping and format conversion
+     * of the payload.  \sa FIXME.
+     *
+     * \returns true if the object wants to be called again with new data;
+     * false if no additional data is wanted.
+     */
+    virtual bool operator()(const uint32_t *payload,
+			    size_t n32_bit_words,
+			    const expanded_header *hdr);
+  };
+
+};  // vrt
+
+
+#endif /* INCLUDED_VRT_RX_PACKET_HANDLER_H */
diff --git a/vrt/lib/Makefile.am b/vrt/lib/Makefile.am
new file mode 100644
index 000000000..9832c0cd5
--- /dev/null
+++ b/vrt/lib/Makefile.am
@@ -0,0 +1,50 @@
+#
+# Copyright 2007,2008,2009 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+include $(top_srcdir)/Makefile.common
+
+AM_CPPFLAGS = \
+    $(VRT_INCLUDES) \
+    $(BOOST_CPPFLAGS) \
+    $(CPPUNIT_INCLUDES)
+
+bin_PROGRAMS = 
+
+lib_LTLIBRARIES = \
+	libvrt.la
+
+libvrt_la_SOURCES = \
+	copiers.cc \
+	data_handler.cc \
+	expanded_header.cc \
+	quadradio.cc \
+	rx.cc \
+	rx_packet_handler.cc \
+	socket_rx_buffer.cc
+
+libvrt_la_LIBADD =
+
+# Private headers not needed for above the API development
+noinst_HEADERS = \
+	data_handler.h \
+	expanded_header_cw_tables.h \
+	expanded_header_switch_body.h \
+	socket_rx_buffer.h
+
+EXTRA_DIST = \
+	gen_cw_tables.py \
+	gen_switch_body.py
diff --git a/vrt/lib/copiers.cc b/vrt/lib/copiers.cc
new file mode 100644
index 000000000..aa2846af5
--- /dev/null
+++ b/vrt/lib/copiers.cc
@@ -0,0 +1,69 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <vrt/copiers.h>
+#include <arpa/inet.h>
+
+namespace vrt {
+
+  void 
+  copy_net_16sc_to_host_16sc(size_t nitems,
+			     const uint32_t *items,
+			     std::complex<int16_t> *host_items)
+  {
+#ifdef WORDS_BIGENDIAN
+
+    assert(sizeof(items[0]) == sizeof(host_items[0]));
+    memcpy(host_items, items, nitems * sizeof(items[0]));
+
+#else
+
+    // FIXME SIMD welcome here
+
+    for (size_t i = 0; i < nitems; i++){
+      uint32_t t = ntohl(items[i]);
+      //printf("%9d\n", items[i]);
+      host_items[i] = std::complex<int16_t>((t >> 16), t & 0xffff);
+    }
+
+#endif
+  }
+
+  void
+  copy_net_16sc_to_host_32fc(size_t nitems,
+			     const uint32_t *items,
+			     std::complex<float> *host_items)
+  {
+    // FIXME SIMD welcome here
+
+    for (size_t i = 0; i < nitems; i++){
+      uint32_t t = ntohl(items[i]);
+      int16_t re = (t >> 16) & 0xffff;
+      int16_t im = (t & 0xffff);
+      host_items[i] = std::complex<float>(re * 1.0/32768, im * 1.0/32768);
+    }
+  }
+
+};
+
diff --git a/vrt/lib/data_handler.cc b/vrt/lib/data_handler.cc
new file mode 100644
index 000000000..7d1f73a9a
--- /dev/null
+++ b/vrt/lib/data_handler.cc
@@ -0,0 +1,32 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008,2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "data_handler.h"
+
+namespace vrt {
+  
+  data_handler::~data_handler()
+  {
+    // default nop destructor
+  }
+
+}
+  
diff --git a/vrt/lib/data_handler.h b/vrt/lib/data_handler.h
new file mode 100644
index 000000000..c041e48be
--- /dev/null
+++ b/vrt/lib/data_handler.h
@@ -0,0 +1,53 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008,2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef INCLUDED_VRT_DATA_HANDLER_H
+#define INCLUDED_VRT_DATA_HANDLER_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+namespace vrt {
+
+  /*!
+   * \brief Abstract function object called to handle received data blocks.
+   */
+  class data_handler 
+  {
+  public:
+
+    enum result_bits {
+      DONE	= 0x0002,    	//< do not call this object again
+    };
+    
+    typedef int result;		//< bitmask of result_bits
+
+    /*!
+     * \param base points to the beginning of the data
+     * \param len is the length in bytes of the data
+     * \returns bitmask composed of DONE
+     */
+    virtual result operator()(const void *base, size_t len) = 0;
+    virtual ~data_handler();
+  };
+
+} // namespace vrt
+
+#endif /* INCLUDED_VRT_DATA_HANDLER_H */
diff --git a/vrt/lib/expanded_header.cc b/vrt/lib/expanded_header.cc
new file mode 100644
index 000000000..d5c4ea888
--- /dev/null
+++ b/vrt/lib/expanded_header.cc
@@ -0,0 +1,119 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <vrt/expanded_header.h>
+#include <arpa/inet.h>			// needs autoconf'ing
+//#include <stdio.h>
+
+namespace vrt {
+
+  // lookup tables indexed by packet type
+  unsigned char expanded_header::s_if_data[16] = {
+    1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+  };
+
+  unsigned char expanded_header::s_ext_data[16] = {
+    0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+  };
+
+  unsigned char expanded_header::s_data[16] = {
+    1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+  };
+
+  unsigned char expanded_header::s_context[16] = {
+    0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+  };
+
+  unsigned char expanded_header::s_stream_id[16] = {
+    0, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+  };
+
+
+  // dispatch codeword bits
+  static const int HAS_STREAM_ID       = 1 << 0;
+  static const int HAS_CLASS_ID        = 1 << 1;
+  static const int HAS_INTEGER_SECS    = 1 << 2;
+  static const int HAS_FRACTIONAL_SECS = 1 << 3;
+  static const int HAS_TRAILER         = 1 << 4;
+
+#include "expanded_header_cw_tables.h"
+
+  static int
+  compute_codeword(const expanded_header &h)
+  {
+    int cw = 0;
+    if (h.stream_id_p())       cw |= HAS_STREAM_ID;
+    if (h.class_id_p())        cw |= HAS_CLASS_ID;
+    if (h.integer_secs_p())    cw |= HAS_INTEGER_SECS;
+    if (h.fractional_secs_p()) cw |= HAS_FRACTIONAL_SECS;
+    if (h.trailer_p())         cw |= HAS_TRAILER;
+    return cw;
+  }
+
+  bool 
+  expanded_header::parse(const uint32_t *packet,	// in
+			size_t n32_bit_words_packet,	// in
+			expanded_header *h,		// out
+			const uint32_t **payload,	// out
+			size_t *n32_bit_words_payload)	// out
+  {
+    size_t len = n32_bit_words_packet;
+    const uint32_t *p = packet;
+
+    *payload = 0;
+    *n32_bit_words_payload = 0;
+
+    // printf("parse: n32_bit_words_packet = %zd\n", n32_bit_words_packet);
+
+    if (len < 1){		// must have at least the header word
+      h->header = 0;
+      return false;
+    }
+
+    h->header = ntohl(p[0]);
+
+    if (h->pkt_size() > len)
+      return false;		// VRT header says packet is bigger than what we've got
+
+    len = h->pkt_size();	// valid length of packet
+
+    int cw = compute_codeword(*h);
+    if (cw_header_len(cw) + cw_trailer_len(cw) > len)
+      return false;		// negative payload len
+
+    *payload = p + cw_header_len(cw);
+    *n32_bit_words_payload = len - (cw_header_len(cw) + cw_trailer_len(cw));
+
+    // printf("parse: hdr = 0x%08x, cw = 0x%02x, cw_header_len(cw) = %d, cw_trailer_len(cw) = %d\n",
+    //   h->header, cw, cw_header_len(cw), cw_trailer_len(cw));
+
+    switch (cw & 0x1f){
+#include "expanded_header_switch_body.h"
+    }
+
+    return true;
+  }
+
+
+}; // vrt
diff --git a/vrt/lib/expanded_header_cw_tables.h b/vrt/lib/expanded_header_cw_tables.h
new file mode 100644
index 000000000..fbb9c6b81
--- /dev/null
+++ b/vrt/lib/expanded_header_cw_tables.h
@@ -0,0 +1,14 @@
+inline static size_t cw_header_len(int cw){
+  static const size_t s_cw_header_len[32] = {
+    1, 2, 3, 4, 2, 3, 4, 5, 3, 4, 5, 6, 4, 5, 6, 7, 1, 2, 3, 4, 2, 3, 4, 5, 3, 4, 5, 6, 4, 5, 6, 7, 
+  };
+  return s_cw_header_len[cw];
+}
+
+inline static size_t cw_trailer_len(int cw){
+  static const size_t s_cw_trailer_len[32] = {
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
+  };
+  return s_cw_trailer_len[cw];
+}
+
diff --git a/vrt/lib/expanded_header_switch_body.h b/vrt/lib/expanded_header_switch_body.h
new file mode 100644
index 000000000..40e575c2c
--- /dev/null
+++ b/vrt/lib/expanded_header_switch_body.h
@@ -0,0 +1,256 @@
+  case 0:
+    h->stream_id = 0;
+    h->class_id = 0;
+    h->integer_secs = 0;
+    h->fractional_secs = 0;
+    h->trailer = 0;
+    break;
+
+  case 1:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = 0;
+    h->integer_secs = 0;
+    h->fractional_secs = 0;
+    h->trailer = 0;
+    break;
+
+  case 2:
+    h->stream_id = 0;
+    h->class_id = ((uint64_t)(ntohl(p[1])) << 32) | ntohl(p[2]);
+    h->integer_secs = 0;
+    h->fractional_secs = 0;
+    h->trailer = 0;
+    break;
+
+  case 3:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->integer_secs = 0;
+    h->fractional_secs = 0;
+    h->trailer = 0;
+    break;
+
+  case 4:
+    h->stream_id = 0;
+    h->class_id = 0;
+    h->integer_secs = ntohl(p[1]);
+    h->fractional_secs = 0;
+    h->trailer = 0;
+    break;
+
+  case 5:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = 0;
+    h->integer_secs = ntohl(p[2]);
+    h->fractional_secs = 0;
+    h->trailer = 0;
+    break;
+
+  case 6:
+    h->stream_id = 0;
+    h->class_id = ((uint64_t)(ntohl(p[1])) << 32) | ntohl(p[2]);
+    h->integer_secs = ntohl(p[3]);
+    h->fractional_secs = 0;
+    h->trailer = 0;
+    break;
+
+  case 7:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->integer_secs = ntohl(p[4]);
+    h->fractional_secs = 0;
+    h->trailer = 0;
+    break;
+
+  case 8:
+    h->stream_id = 0;
+    h->class_id = 0;
+    h->integer_secs = 0;
+    h->fractional_secs = ((uint64_t)(ntohl(p[1])) << 32) | ntohl(p[2]);
+    h->trailer = 0;
+    break;
+
+  case 9:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = 0;
+    h->integer_secs = 0;
+    h->fractional_secs = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->trailer = 0;
+    break;
+
+  case 10:
+    h->stream_id = 0;
+    h->class_id = ((uint64_t)(ntohl(p[1])) << 32) | ntohl(p[2]);
+    h->integer_secs = 0;
+    h->fractional_secs = ((uint64_t)(ntohl(p[3])) << 32) | ntohl(p[4]);
+    h->trailer = 0;
+    break;
+
+  case 11:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->integer_secs = 0;
+    h->fractional_secs = ((uint64_t)(ntohl(p[4])) << 32) | ntohl(p[5]);
+    h->trailer = 0;
+    break;
+
+  case 12:
+    h->stream_id = 0;
+    h->class_id = 0;
+    h->integer_secs = ntohl(p[1]);
+    h->fractional_secs = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->trailer = 0;
+    break;
+
+  case 13:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = 0;
+    h->integer_secs = ntohl(p[2]);
+    h->fractional_secs = ((uint64_t)(ntohl(p[3])) << 32) | ntohl(p[4]);
+    h->trailer = 0;
+    break;
+
+  case 14:
+    h->stream_id = 0;
+    h->class_id = ((uint64_t)(ntohl(p[1])) << 32) | ntohl(p[2]);
+    h->integer_secs = ntohl(p[3]);
+    h->fractional_secs = ((uint64_t)(ntohl(p[4])) << 32) | ntohl(p[5]);
+    h->trailer = 0;
+    break;
+
+  case 15:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->integer_secs = ntohl(p[4]);
+    h->fractional_secs = ((uint64_t)(ntohl(p[5])) << 32) | ntohl(p[6]);
+    h->trailer = 0;
+    break;
+
+  case 16:
+    h->stream_id = 0;
+    h->class_id = 0;
+    h->integer_secs = 0;
+    h->fractional_secs = 0;
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 17:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = 0;
+    h->integer_secs = 0;
+    h->fractional_secs = 0;
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 18:
+    h->stream_id = 0;
+    h->class_id = ((uint64_t)(ntohl(p[1])) << 32) | ntohl(p[2]);
+    h->integer_secs = 0;
+    h->fractional_secs = 0;
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 19:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->integer_secs = 0;
+    h->fractional_secs = 0;
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 20:
+    h->stream_id = 0;
+    h->class_id = 0;
+    h->integer_secs = ntohl(p[1]);
+    h->fractional_secs = 0;
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 21:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = 0;
+    h->integer_secs = ntohl(p[2]);
+    h->fractional_secs = 0;
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 22:
+    h->stream_id = 0;
+    h->class_id = ((uint64_t)(ntohl(p[1])) << 32) | ntohl(p[2]);
+    h->integer_secs = ntohl(p[3]);
+    h->fractional_secs = 0;
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 23:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->integer_secs = ntohl(p[4]);
+    h->fractional_secs = 0;
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 24:
+    h->stream_id = 0;
+    h->class_id = 0;
+    h->integer_secs = 0;
+    h->fractional_secs = ((uint64_t)(ntohl(p[1])) << 32) | ntohl(p[2]);
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 25:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = 0;
+    h->integer_secs = 0;
+    h->fractional_secs = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 26:
+    h->stream_id = 0;
+    h->class_id = ((uint64_t)(ntohl(p[1])) << 32) | ntohl(p[2]);
+    h->integer_secs = 0;
+    h->fractional_secs = ((uint64_t)(ntohl(p[3])) << 32) | ntohl(p[4]);
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 27:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->integer_secs = 0;
+    h->fractional_secs = ((uint64_t)(ntohl(p[4])) << 32) | ntohl(p[5]);
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 28:
+    h->stream_id = 0;
+    h->class_id = 0;
+    h->integer_secs = ntohl(p[1]);
+    h->fractional_secs = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 29:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = 0;
+    h->integer_secs = ntohl(p[2]);
+    h->fractional_secs = ((uint64_t)(ntohl(p[3])) << 32) | ntohl(p[4]);
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 30:
+    h->stream_id = 0;
+    h->class_id = ((uint64_t)(ntohl(p[1])) << 32) | ntohl(p[2]);
+    h->integer_secs = ntohl(p[3]);
+    h->fractional_secs = ((uint64_t)(ntohl(p[4])) << 32) | ntohl(p[5]);
+    h->trailer = ntohl(p[len-1]);
+    break;
+
+  case 31:
+    h->stream_id = ntohl(p[1]);
+    h->class_id = ((uint64_t)(ntohl(p[2])) << 32) | ntohl(p[3]);
+    h->integer_secs = ntohl(p[4]);
+    h->fractional_secs = ((uint64_t)(ntohl(p[5])) << 32) | ntohl(p[6]);
+    h->trailer = ntohl(p[len-1]);
+    break;
+
diff --git a/vrt/lib/gen_cw_tables.py b/vrt/lib/gen_cw_tables.py
new file mode 100755
index 000000000..803a392e8
--- /dev/null
+++ b/vrt/lib/gen_cw_tables.py
@@ -0,0 +1,69 @@
+#!/usr/bin/env python
+#
+# Copyright 2009 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+# 
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+
+import sys
+
+# dispatch codeword bits
+HAS_STREAM_ID       = 1 << 0;
+HAS_CLASS_ID        = 1 << 1;
+HAS_INTEGER_SECS    = 1 << 2;
+HAS_FRACTIONAL_SECS = 1 << 3;
+HAS_TRAILER         = 1 << 4;
+
+def main():
+    f = sys.stdout
+    header_len  = 32 * [0]
+    trailer_len = 32 * [0]
+
+    for cw in range(32):
+        t = 0
+        if cw & HAS_TRAILER:         t += 1
+        trailer_len[cw] = t
+
+        t = 1
+        if cw & HAS_STREAM_ID:       t += 1
+        if cw & HAS_CLASS_ID:        t += 2
+        if cw & HAS_INTEGER_SECS:    t += 1
+        if cw & HAS_FRACTIONAL_SECS: t += 2
+        header_len[cw] = t
+
+    write_table(f, "cw_header_len", header_len)
+    write_table(f, "cw_trailer_len", trailer_len)
+    
+def write_table(f, name, table):
+    f.write("inline static size_t ")
+    f.write(name)
+    f.write("(int cw){\n")
+
+    f.write("  static const size_t s_")
+    f.write(name)
+    f.write("[32] = {\n    ")
+    for t in table:
+        f.write("%d, " % (t,))
+    f.write("\n  };\n")
+
+    f.write("  return s_")
+    f.write(name)
+    f.write("[cw];\n}\n\n")
+
+
+if __name__ == '__main__':
+    main()
diff --git a/vrt/lib/gen_switch_body.py b/vrt/lib/gen_switch_body.py
new file mode 100755
index 000000000..105fa76a7
--- /dev/null
+++ b/vrt/lib/gen_switch_body.py
@@ -0,0 +1,80 @@
+#!/usr/bin/env python
+#
+# Copyright 2009 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+# 
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+
+import sys
+
+# dispatch codeword bits
+HAS_STREAM_ID       = 1 << 0;
+HAS_CLASS_ID        = 1 << 1;
+HAS_INTEGER_SECS    = 1 << 2;
+HAS_FRACTIONAL_SECS = 1 << 3;
+HAS_TRAILER         = 1 << 4;
+
+def do_case(f, cw):
+
+    def do32(name, mask, index):
+        f.write("    ")
+        if cw & mask:
+            f.write("h->%s = ntohl(p[%d]);\n" % (name, index))
+            return 1
+        else:
+            f.write("h->%s = 0;\n" % (name,))
+            return 0
+        
+    def do64(name, mask, index):
+        f.write("    ")
+        if cw & mask:
+            f.write("h->%s = ((uint64_t)(ntohl(p[%d])) << 32) | ntohl(p[%d]);\n" % (name, index, index+1))
+            return 2
+        else:
+            f.write("h->%s = 0;\n" % (name,))
+            return 0
+
+    def dotrailer(name, mask):
+        f.write("    ")
+        if cw & mask:
+            f.write("h->%s = ntohl(p[len-1]);\n" % (name,))
+            return 1
+        else:
+            f.write("h->%s = 0;\n" % (name,))
+            return 0
+        
+    f.write("  case %d:\n" % (cw,))
+
+    index = 1
+    index += do32("stream_id", HAS_STREAM_ID, index)
+    index += do64("class_id",  HAS_CLASS_ID,  index)
+    index += do32("integer_secs", HAS_INTEGER_SECS, index)
+    index += do64("fractional_secs", HAS_FRACTIONAL_SECS, index)
+    dotrailer("trailer", HAS_TRAILER)
+    
+    f.write("    break;\n\n")
+        
+
+def main():
+    f = sys.stdout
+
+    for cw in range(32):
+        do_case(f, cw)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/vrt/lib/quadradio.cc b/vrt/lib/quadradio.cc
new file mode 100644
index 000000000..ab5de89b8
--- /dev/null
+++ b/vrt/lib/quadradio.cc
@@ -0,0 +1,408 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <vrt/quadradio.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdexcept>
+#include <math.h>
+
+#define	MIN_IP_LOCAL_PORT	32768
+#define	MAX_IP_LOCAL_PORT	61000
+
+#define ALL_DBOARDS	0xf
+
+static bool
+send_and_check(int fd, void *buf, size_t len)
+{
+  int r = send(fd, buf, len, 0);
+  if (r < 0){
+    perror("send");
+    return false;
+  }
+  if ((size_t) r != len){
+    fprintf(stderr, "send: short return value.  expected %zd, got %d\n", len, r);
+    return false;
+  }
+  return true;
+}
+
+
+vrt::quadradio::quadradio(const std::string &ip, size_t rx_bufsize)
+  : d_ctrl_fd(0), d_data_fd(0), d_data_port(0),
+  d_band_select(0), d_rx_antenna(0), d_attenuation0(0), d_attenuation1(0)//d_10dB_atten(true)
+{
+  if (!open(ip.c_str()))
+    throw std::runtime_error("vrt::quadradio: failed to open " + ip + "\n");
+
+  d_rx = vrt::rx::make(data_socket_fd(), rx_bufsize);
+  set_test_signal(VRT_TEST_SIG_NORMAL);
+}
+
+vrt::quadradio::~quadradio()
+{
+  ::close(d_ctrl_fd);
+}
+
+bool
+vrt::quadradio::open(const char *ip)
+{
+  return open_sockets(ip, control_port(),
+		      &d_ctrl_fd, &d_ctrl_port_inaddr,
+		      &d_data_fd, &d_data_port);
+}
+
+bool
+vrt::quadradio::start_streaming(int samples_per_pkt)
+{
+  return send_rx_command(d_ctrl_fd, true, d_ctrl_port_inaddr,
+			 d_data_port, samples_per_pkt, 0);
+}
+
+bool
+vrt::quadradio::stop_streaming()
+{
+  return send_stop_rx_command(d_ctrl_fd);
+}
+
+bool
+vrt::quadradio::set_center_freq(double target_freq){
+    if (target_freq < 700e6) return false;
+    if (target_freq <= 1.0e9) return set_band_select("A");
+    if (target_freq <= 1.5e9) return set_band_select("B");
+    if (target_freq <= 2.2e9) return set_band_select("C");
+    if (target_freq <= 3.0e9) return set_band_select("D");
+    return false;
+}
+
+bool
+vrt::quadradio::set_band_select(const std::string &band){
+    if (band == "A") d_band_select = 3;
+    else if (band == "B") d_band_select = 2;
+    else if (band == "C") d_band_select = 1;
+    else if (band == "D") d_band_select = 0;
+    else return false;
+    update_dboard_pins();
+    return true;
+}
+
+//void
+//vrt::quadradio::set_10dB_atten(bool on){
+//    d_10dB_atten = on;
+//    update_dboard_pins();
+//}
+
+bool
+vrt::quadradio::select_rx_antenna(const std::string &ant){
+    if (ant == "rf") d_rx_antenna = 0;
+    else if (ant == "cal") d_rx_antenna = 1;
+    else return true;
+    update_dboard_pins();
+    return true;
+}
+
+bool
+vrt::quadradio::set_attenuation0(int attenuation){
+    if (attenuation < 0 || attenuation > 31) return false;
+    d_attenuation0 = attenuation;
+    update_dboard_pins();
+    return true;
+}
+
+bool
+vrt::quadradio::set_attenuation1(int attenuation){
+    if (attenuation < 0 || attenuation > 31) return false;
+    d_attenuation1 = attenuation;
+    update_dboard_pins();
+    return true;
+}
+
+//bit reversal, length in bits
+static int reverse_bits(int input, int len){
+    int reversed = 0;
+    for (int i = 0; i < len; i++){
+        reversed += (input & (1<<i))?(1 << (len-i-1)):0;
+    }
+    return reversed;
+}
+
+void
+vrt::quadradio::update_dboard_pins(void){
+    int db_ctrl = \
+        ((reverse_bits(d_attenuation0, 5) & 0x1f) << 10) | \
+        ((reverse_bits(~d_attenuation1, 5) & 0x1f) << 03) | \
+        ((d_band_select                   & 0x03) << 01) | \
+        ((d_rx_antenna                    & 0x01) << 00);
+    set_dboard_pins(ALL_DBOARDS, db_ctrl);  // FIXME sets them all
+}
+
+void
+vrt::quadradio::set_adc_gain(bool on){
+  set_hsadc_conf(ALL_DBOARDS, 0x14, on ? 0x90 : 0x80);
+}
+
+void
+vrt::quadradio::set_dc_offset_comp(bool on){
+    if (on) {
+        set_hsadc_conf(ALL_DBOARDS, 0x1B, 0x80);
+        set_hsadc_conf(ALL_DBOARDS, 0x1A, 0x00); //bits 6:4 set time constant
+    }
+    else set_hsadc_conf(ALL_DBOARDS, 0x1B, 0x00);
+}
+
+void
+vrt::quadradio::set_digital_gain(float gain){
+    int gain_q1 = static_cast<int>(round(gain*2.0));
+    set_hsadc_conf(ALL_DBOARDS, 0x17, gain_q1);
+}
+
+void
+vrt::quadradio::set_test_signal(vrt_test_sig_t type){
+    set_hsadc_conf(ALL_DBOARDS, 0x16, type);
+}
+
+bool
+vrt::quadradio::open_sockets(const char *quad_radio_ip, int quad_radio_ctrl_port,
+			     int *ctrl_fd_ptr, struct in_addr *ctrl_port_inaddr,
+			     int *data_fd_ptr, int *data_port_ptr)
+{
+  int	ctrl_fd;	// socket for control
+  int	data_fd;	// socket fd for data
+  int	data_port;	// our port number
+
+  //
+  // create a udp socket and connect it to the quad radio control port
+  //
+
+  ctrl_fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+  if (ctrl_fd == -1){
+    perror("socket: ctrl_fd");
+    return false;
+  }
+
+  struct sockaddr_in si_other;
+  memset(&si_other, 0, sizeof(si_other));
+  si_other.sin_family = AF_INET;
+  si_other.sin_port = htons(quad_radio_ctrl_port);
+  if (inet_pton(AF_INET, quad_radio_ip, &si_other.sin_addr) <= 0){
+    perror("inet_pton");
+    return false;
+  }
+
+  if (connect(ctrl_fd, (struct sockaddr *) &si_other, sizeof(si_other)) != 0){
+    perror("connect");
+    return false;
+  }
+
+  // get our ip address associated with the interface connected to the control port
+
+  struct sockaddr_in si_me;
+  memset(&si_me, 0, sizeof(si_me));
+  socklen_t sockname_len = sizeof(si_me);
+  if (getsockname(ctrl_fd, (struct sockaddr *) &si_me, &sockname_len) != 0){
+    perror("getsockname");
+  }
+  
+  *ctrl_port_inaddr = si_me.sin_addr;
+
+  if (1){
+    char buf[128];
+    const char *s = inet_ntop(si_me.sin_family, &si_me.sin_addr, buf, sizeof(buf));
+    if (s == 0){
+      perror("inet_ntop");
+      return false;
+    }
+    // printf("our ip addr associated with ctrl port: %s\n", s);
+  }
+  
+  //
+  // create a udp socket to use to receive data
+  //
+
+  data_fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+  if (data_fd == -1){
+    perror("socket: data_fd");
+    return false;
+  }
+
+  // bind it to a local port on the interface that connects to the ctrl port.
+  // FIXME this assumes that interface connected to the control port and the
+  //   interface connected to the data port are the same.  If we're using
+  //   both ethernet ports on the quad radio, this may not be the case.
+
+  data_port = -1;
+  for (int port = MIN_IP_LOCAL_PORT; port <= MAX_IP_LOCAL_PORT; port++){
+    struct sockaddr_in si_me;
+    memset(&si_me, 0, sizeof(si_me));
+    si_me.sin_family = AF_INET;
+    si_me.sin_port = htons(port);
+    si_me.sin_addr.s_addr = htonl(INADDR_ANY);
+
+    if (bind(data_fd, (struct sockaddr *) &si_me, sizeof(si_me)) == 0){	// found one!
+      data_port = port;
+      break;
+    }
+  }
+
+  if (data_port == -1){
+    fprintf(stderr, "failed to bind to a local port\n");
+    return false;
+  }
+
+  // printf("our data port = %d\n", data_port);
+
+  *ctrl_fd_ptr = ctrl_fd;
+  *data_fd_ptr = data_fd;
+  *data_port_ptr = data_port;
+
+  return true;
+}
+
+// ------------------------------------------------------------------------
+
+bool
+vrt::quadradio::send_rx_command(int ctrl_fd, bool start,
+				struct in_addr addr, int data_port,
+				int samples_per_pkt, int siggen_param)
+{
+  uint32_t cmd[7];
+  cmd[0] = htonl(0);		   // verb: set
+  cmd[1] = htonl(0);		   // id: rx_streaming
+  cmd[2] = htonl(start ? 1: 0);	   // start or stop?
+  cmd[3] = addr.s_addr;	  	   // ip address to send data to (already network endian)
+  cmd[4] = htonl(data_port);	   // port to send data to
+  cmd[5] = htonl(samples_per_pkt);
+  cmd[6] = htonl(siggen_param);
+
+  return send_and_check(ctrl_fd, cmd, sizeof(cmd));
+}
+
+bool
+vrt::quadradio::send_stop_rx_command(int ctrl_fd)
+{
+  struct in_addr in_addr;
+  in_addr.s_addr = 0;
+  return send_rx_command(ctrl_fd, false, in_addr, 0, 0, 0);
+}
+
+bool
+vrt::quadradio::set_dboard_pins(int dboard_bitmask, int v)
+{
+  uint32_t cmd[4];
+  cmd[0] = htonl(0);		   // verb: set
+  cmd[1] = htonl(1);		   // id: dboard_pins
+  cmd[2] = htonl(dboard_bitmask);
+  cmd[3] = htonl(v);	   	   // value
+
+  return send_and_check(d_ctrl_fd, cmd, sizeof(cmd));
+}
+  
+bool
+vrt::quadradio::set_setting_reg(int regno, int value)
+{
+  uint32_t cmd[4];
+  cmd[0] = htonl(0);		   // verb: set
+  cmd[1] = htonl(2);		   // id: SR
+  cmd[2] = htonl(regno);
+  cmd[3] = htonl(value);
+
+  return send_and_check(d_ctrl_fd, cmd, sizeof(cmd));
+}
+
+bool
+vrt::quadradio::set_hsadc_conf(int dboard_bitmask, int regno, int value)
+{
+  uint32_t cmd[5];
+  cmd[0] = htonl(0);		   // verb: set
+  cmd[1] = htonl(3);		   // id: HSADC_CONF
+  cmd[2] = htonl(dboard_bitmask);
+  cmd[3] = htonl(regno);
+  cmd[4] = htonl(value);
+
+  return send_and_check(d_ctrl_fd, cmd, sizeof(cmd));
+}
+
+bool
+vrt::quadradio::set_lsdac(int dboard_bitmask, int which_dac, int value)
+{
+  uint32_t cmd[5];
+  cmd[0] = htonl(0);		   // verb: set
+  cmd[1] = htonl(4);		   // id: LSDAC
+  cmd[2] = htonl(dboard_bitmask);
+  cmd[3] = htonl(which_dac);
+  cmd[4] = htonl(value);
+
+  return send_and_check(d_ctrl_fd, cmd, sizeof(cmd));
+}
+
+bool
+vrt::quadradio::set_mem32(int addr, int value)
+{
+  uint32_t cmd[4];
+  cmd[0] = htonl(0);		   // verb: set
+  cmd[1] = htonl(5);		   // id: MEM32
+  cmd[2] = htonl(addr);
+  cmd[3] = htonl(value);
+
+  return send_and_check(d_ctrl_fd, cmd, sizeof(cmd));
+}
+
+bool
+vrt::quadradio::set_lo_freq(double freq)
+{
+  uint64_t lo_freq = uint64_t(freq * (uint64_t(1)<<20)); //q20 format
+  uint32_t cmd[4];
+  cmd[0] = htonl(0);		   // verb: set
+  cmd[1] = htonl(6);		   // id: lo freq
+  cmd[2] = htonl((lo_freq >> 32) & 0xffffffff);
+  cmd[3] = htonl((lo_freq >> 0) & 0xffffffff);
+
+  return send_and_check(d_ctrl_fd, cmd, sizeof(cmd));
+}
+
+bool
+vrt::quadradio::set_cal_freq(double freq)
+{
+  uint64_t cal_freq = uint64_t(freq * (uint64_t(1)<<20)); //q20 format
+  uint32_t cmd[4];
+  cmd[0] = htonl(0);		   // verb: set
+  cmd[1] = htonl(7);		   // id: cal freq
+  cmd[2] = htonl((cal_freq >> 32) & 0xffffffff);
+  cmd[3] = htonl((cal_freq >> 0) & 0xffffffff);
+
+  return send_and_check(d_ctrl_fd, cmd, sizeof(cmd));
+}
+
+bool
+vrt::quadradio::set_beamforming(int32_t gains[8]){
+  uint32_t cmd[2+8];
+  cmd[0] = htonl(0);		   // verb: set
+  cmd[1] = htonl(8);		   // id: beamformin
+  for (int i = 0; i < 8; i++){
+    //printf("%d\n", gains[i]);
+    cmd[i+2] = htonl(gains[i]); 
+  }
+  return send_and_check(d_ctrl_fd, cmd, sizeof(cmd));
+}
+
diff --git a/vrt/lib/rx.cc b/vrt/lib/rx.cc
new file mode 100644
index 000000000..f75db3111
--- /dev/null
+++ b/vrt/lib/rx.cc
@@ -0,0 +1,120 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <vrt/rx.h>
+#include <vrt/expanded_header.h>
+#include "socket_rx_buffer.h"
+#include "data_handler.h"
+#include <unistd.h>
+#include <stdio.h>
+#include <stdexcept>
+
+static void
+print_words(FILE *fp, size_t offset, uint32_t *buf, size_t n)
+{
+  size_t i;
+  for (i = 0; i < n; i++){
+    if (i % 4 == 0){
+      fprintf(fp, "%04zx:", i);
+    }
+
+    putc(' ', fp);
+    fprintf(fp, "%08x", buf[i]);
+    if (i % 4 == 3)
+      putc('\n', fp);
+  }
+
+  putc('\n', fp);
+}
+
+
+
+namespace vrt {
+  
+  rx::sptr
+  rx::make(int socket_fd, size_t rx_bufsize)
+  {
+    return sptr(new rx(socket_fd, rx_bufsize));
+  }
+
+  rx::rx(int socket_fd, size_t rx_bufsize)
+    : d_socket_fd(socket_fd),
+      d_srb(new socket_rx_buffer(socket_fd, rx_bufsize))
+  {
+  }
+
+  rx::~rx()
+  {
+    delete d_srb;
+    ::close(d_socket_fd);
+  }
+
+
+  class vrt_data_handler : public data_handler
+  {
+    rx_packet_handler	*d_handler;
+
+  public:
+    vrt_data_handler(rx_packet_handler *handler)
+      : d_handler(handler){}
+
+    ~vrt_data_handler();
+
+    result operator()(const void *base, size_t len);
+  };
+
+  vrt_data_handler::~vrt_data_handler(){}
+
+  data_handler::result
+  vrt_data_handler::operator()(const void *base, size_t len)
+  {
+#if 0
+    print_words(0, (uint32_t *)base, len/(sizeof(uint32_t)));
+    return 0;
+#else
+    const uint32_t *payload;
+    size_t n32_bit_words;
+    expanded_header hdr;
+    if (!expanded_header::parse((const uint32_t*) base, len/(sizeof(uint32_t)),
+				&hdr, &payload, &n32_bit_words)){
+      if (1){
+	fprintf(stderr, "vrt_data_handler: malformed VRT packet!\n");
+	print_words(stderr, 0, (uint32_t *)base, len/(sizeof(uint32_t)));
+      }
+      return 0;
+    }
+    bool want_more = (*d_handler)(payload, n32_bit_words, &hdr);
+    return !want_more ? data_handler::DONE : 0;
+#endif
+  }
+
+
+  bool
+  rx::rx_packets(rx_packet_handler *handler, bool dont_wait)
+  {
+    vrt_data_handler h(handler);
+    socket_rx_buffer::result r = d_srb->rx_frames(&h, dont_wait ? 0 : -1);
+    return r == socket_rx_buffer::EB_OK || r == socket_rx_buffer::EB_WOULD_BLOCK;
+  }
+
+}; // vrt
diff --git a/vrt/lib/rx_packet_handler.cc b/vrt/lib/rx_packet_handler.cc
new file mode 100644
index 000000000..11f90278d
--- /dev/null
+++ b/vrt/lib/rx_packet_handler.cc
@@ -0,0 +1,41 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <vrt/rx_packet_handler.h>
+
+namespace vrt {
+
+  rx_packet_handler::~rx_packet_handler(){}
+
+  // default operator is a NOP
+  bool 
+  rx_packet_handler::operator()(const uint32_t *payload,
+				size_t n32_bit_words,
+				const expanded_header *hdr)
+  {
+    return true;
+  }
+
+
+}; // vrt
diff --git a/vrt/lib/socket_rx_buffer.cc b/vrt/lib/socket_rx_buffer.cc
new file mode 100644
index 000000000..6ed211b9a
--- /dev/null
+++ b/vrt/lib/socket_rx_buffer.cc
@@ -0,0 +1,278 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008,2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "socket_rx_buffer.h"
+#include "data_handler.h"
+#include <linux/if_packet.h>
+#include <sys/socket.h>
+#include <sys/mman.h>
+#include <sys/poll.h>
+#include <iostream>
+#include <cmath>
+#include <errno.h>
+#include <stdexcept>
+#include <string.h>
+#include <fcntl.h>
+#include <cstdio>
+
+
+#define SOCKET_RX_BUFFER_DEBUG      1 // define to 0 or 1
+#if SOCKET_RX_BUFFER_DEBUG
+#define DEBUG_LOG(x) ::write(2, (x), 1)
+#else
+#define DEBUG_LOG(X)
+#endif
+
+#define DEFAULT_MEM_SIZE 62.5e6 // ~0.5s @ 125 MB/s
+#define MAX_MEM_SIZE     1000e6 // ~10.00s @ 100 MB/s. 
+#define MAX_SLAB_SIZE    131072 // 128 KB (FIXME fish out of /proc/slabinfo)
+
+
+namespace vrt {
+
+  const unsigned int socket_rx_buffer::MAX_PKTLEN = 8192;
+  const unsigned int socket_rx_buffer::MIN_PKTLEN = 64;
+  
+  socket_rx_buffer::socket_rx_buffer(int socket_fd, size_t rx_bufsize)
+    : d_fd(socket_fd), d_using_tpring(false), d_buflen(0), d_buf(0), d_frame_nr(0),
+      d_frame_size(0), d_head(0), d_ring(0)
+  {
+    if (rx_bufsize == 0)
+      d_buflen = (size_t)DEFAULT_MEM_SIZE;
+    else
+      d_buflen = std::min((size_t)MAX_MEM_SIZE, rx_bufsize);
+
+    if (!open()){
+      throw std::runtime_error("socket_rx_buffer::open failed");
+    }
+  }
+
+  socket_rx_buffer::~socket_rx_buffer()
+  {
+    close();
+  }
+  
+  bool 
+  socket_rx_buffer::open()
+  {
+    if (try_packet_ring()){
+      d_using_tpring = true;
+      // fprintf(stderr, "socket_rx_buffer: using memory mapped interface\n");
+    }
+    else {
+      d_using_tpring = false;
+      // fprintf(stderr, "socket_rx_buffer: NOT using memory mapped interface\n");
+
+      // Increase socket buffer if possible
+
+      int rcvbuf_size = d_buflen;
+#if defined(SO_RCVBUFFORCE)
+      if (setsockopt(d_fd, SOL_SOCKET, SO_RCVBUFFORCE, &rcvbuf_size, sizeof(rcvbuf_size)) != 0){
+	perror("setsockopt(SO_RCVBUFFORCE)");
+	fprintf(stderr, "Are you running as root?  If not, please do.\n");
+      }
+      else {
+	fprintf(stderr, "SO_RCVBUFFORCE = %zd\n", d_buflen);
+      }
+#endif
+    }
+
+    return true;
+  }
+
+  bool
+  socket_rx_buffer::try_packet_ring()
+  {
+    struct tpacket_req req;
+    size_t page_size = getpagesize();
+
+    // Calculate minimum power-of-two aligned size for frames
+    req.tp_frame_size =
+      (unsigned int)rint(pow(2, ceil(log2(TPACKET_ALIGN(TPACKET_HDRLEN)+TPACKET_ALIGN(MAX_PKTLEN)))));
+    d_frame_size = req.tp_frame_size;
+
+    // Calculate minimum contiguous pages needed to enclose a frame
+    int npages = (page_size > req.tp_frame_size) ? 1 : ((req.tp_frame_size+page_size-1)/page_size);
+    req.tp_block_size = page_size << (int)ceil(log2(npages));
+
+    // Calculate number of blocks
+    req.tp_block_nr = (int)(d_buflen/req.tp_block_size);
+			       
+
+    // Recalculate buffer length
+    d_buflen = req.tp_block_nr*req.tp_block_size;
+
+    // Finally, calculate total number of frames.  Since frames, blocks,
+    // and pages are all power-of-two aligned, frames are contiguous
+    req.tp_frame_nr = d_buflen/req.tp_frame_size;
+    d_frame_nr = req.tp_frame_nr;
+
+#if 0
+    if (SOCKET_RX_BUFFER_DEBUG)
+      std::cerr << "socket_rx_buffer:" 
+		<< " frame_size=" << req.tp_frame_size
+		<< " block_size=" << req.tp_block_size
+                << " block_nr=" << req.tp_block_nr
+		<< " frame_nr=" << req.tp_frame_nr
+		<< " buflen=" << d_buflen
+		<< std::endl;
+#endif
+
+    // Try to get kernel shared memory buffer
+    if (setsockopt(d_fd, SOL_PACKET, PACKET_RX_RING, (void *)&req, sizeof(req)) != 0){
+      // perror("socket_rx_buffer: setsockopt");
+      return false;
+    }
+
+    void *p = mmap(0, d_buflen, PROT_READ|PROT_WRITE, MAP_SHARED, d_fd, 0);
+    if (p == MAP_FAILED){
+      perror("socket_rx_buffer: mmap");
+      return false;
+    }
+    d_buf = (uint8_t *) p;
+
+    // Initialize our pointers into the packet ring
+    d_ring.resize(req.tp_frame_nr);
+    for (unsigned int i=0; i < req.tp_frame_nr; i++)
+      d_ring[i] = (uint8_t *)(d_buf+i*req.tp_frame_size);
+
+    return true;
+  }
+
+  bool
+  socket_rx_buffer::close()
+  {
+    return true;
+  }
+
+  inline bool
+  socket_rx_buffer::frame_available()
+  {
+    return (((tpacket_hdr *)d_ring[d_head])->tp_status != TP_STATUS_KERNEL);
+  }
+  
+  socket_rx_buffer::result
+  socket_rx_buffer::rx_frames(data_handler *f, int timeout_in_ms)
+  {
+    if (!d_using_tpring){
+
+      // ----------------------------------------------------------------
+      // Use recv instead of kernel Rx packet ring
+      // ----------------------------------------------------------------
+
+      unsigned char buf[MAX_PKTLEN];
+      bool dont_wait = timeout_in_ms == 0;  	// FIXME treating timeout as 0 or inf
+      int flags = dont_wait ? MSG_DONTWAIT : 0;
+
+      ssize_t rr = recv(d_fd, buf, sizeof(buf), flags);
+      if (rr == -1){		// error?
+	if (errno == EAGAIN){	// non-blocking, nothing there
+	  return EB_WOULD_BLOCK;
+	}
+	perror("rx_frames: recv");
+	return EB_ERROR;
+      }
+
+      // Got first packet.  Call handler
+
+      data_handler::result r = (*f)(buf, rr);
+      if (r & data_handler::DONE)
+	return EB_OK;
+
+      // Now do as many as we can without blocking
+
+      while (1){
+	rr = recv(d_fd, buf, sizeof(buf), MSG_DONTWAIT);
+	if (rr == -1){		// error?
+	  if (errno == EAGAIN)	// non-blocking, nothing there
+	    return EB_OK;	// return OK; we've processed >= 1 packets
+	  perror("rx_frames: recv");
+	  return EB_ERROR;
+	}
+	
+	r = (*f)(buf, rr);
+	if (r & data_handler::DONE)
+	  break;
+      }
+      return EB_OK;
+    }
+
+    // ----------------------------------------------------------------
+    // Use kernel Rx packet ring
+    // ----------------------------------------------------------------
+
+    DEBUG_LOG("\n");
+      
+    while (!frame_available()) {
+      if (timeout_in_ms == 0) {
+        DEBUG_LOG("w");
+        return EB_WOULD_BLOCK;
+      }
+      
+      struct pollfd pfd;
+      pfd.fd = d_fd;
+      pfd.revents = 0;
+      pfd.events = POLLIN;
+
+      // DEBUG_LOG("P");
+
+      int pres = poll(&pfd, 1, timeout_in_ms);
+      if (pres == -1) {
+        perror("poll");
+	return EB_ERROR;
+      }
+
+      if (pres == 0) {
+        DEBUG_LOG("t");
+	return EB_TIMED_OUT;
+      }
+    }
+
+    // Iterate through available packets
+    while (frame_available()) {
+      // Get start of ethernet frame and length
+      tpacket_hdr *hdr = (tpacket_hdr *)d_ring[d_head];
+      void *base = (uint8_t *)hdr+hdr->tp_mac;
+      size_t len = hdr->tp_len;
+      
+      if (1)
+	fprintf(stderr, "socket_rx_buffer: base = %p  tp_mac = %3d  tp_net = %3d\n",
+		base, hdr->tp_mac, hdr->tp_net);
+
+      // Invoke data handler
+      data_handler::result r = (*f)(base, len);
+      hdr->tp_status = TP_STATUS_KERNEL; // mark it free
+
+      inc_head();
+
+      if (r & data_handler::DONE)
+        break;
+    }
+
+    DEBUG_LOG("|");
+    return EB_OK;
+  }
+
+} // namespace vrt
diff --git a/vrt/lib/socket_rx_buffer.h b/vrt/lib/socket_rx_buffer.h
new file mode 100644
index 000000000..053c30c12
--- /dev/null
+++ b/vrt/lib/socket_rx_buffer.h
@@ -0,0 +1,122 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008,2009 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef INCLUDED_VRT_SOCKET_RX_BUFFER_H
+#define INCLUDED_VRT_SOCKET_RX_BUFFER_H
+
+#include <boost/utility.hpp>
+#include <vector>
+#include <memory>
+#include <stdint.h>
+
+namespace vrt {
+
+  class data_handler;
+
+  /*!
+   * \brief high-performance interface to receive datagrams
+   *
+   * On many systems it should be possible to implement this on top of libpcap
+   *
+   * \internal
+   */
+  class socket_rx_buffer : boost::noncopyable 
+  {
+    
+    int		  d_fd;		        // socket file descriptor
+    bool          d_using_tpring;       // using kernel mapped packet ring
+    size_t        d_buflen;             // length of our buffer
+    uint8_t      *d_buf;                // packet ring
+    unsigned int  d_frame_nr;           // max frames on ring
+    size_t        d_frame_size;         // frame storage size
+    unsigned int  d_head;               // pointer to next frame
+
+    std::vector<uint8_t *>  d_ring;     // pointers into buffer
+  
+    bool frame_available();
+
+    void inc_head()
+    {
+      if (d_head + 1 >= d_frame_nr)
+	d_head = 0;
+      else
+	d_head = d_head + 1;
+    }
+
+    bool open();
+    bool close();
+    bool try_packet_ring();
+
+  public:
+
+    enum result {
+      EB_OK,		//< everything's fine
+      EB_ERROR,		//< A non-recoverable error occurred
+      EB_WOULD_BLOCK,	//< A timeout of 0 was specified and nothing was ready
+      EB_TIMED_OUT,	//< The timeout expired before anything was ready
+    };
+
+    static const unsigned int MAX_PKTLEN;
+    static const unsigned int MIN_PKTLEN;
+
+    /*!
+     * \param socket_fd file descriptor that corresponds to a socket
+     * \param rx_bufsize is a hint as to the number of bytes of memory
+     * to allocate for received ethernet frames (0 -> reasonable default)
+     */
+    socket_rx_buffer(int socket_fd, size_t rx_bufsize = 0);
+    ~socket_rx_buffer();
+    
+    /*!
+     * \brief Call \p f for each frame in the receive buffer.
+     * \param f is the frame data handler
+     * \param timeout (in ms) controls behavior when there are no frames to read
+     *
+     * If \p timeout is 0, rx_frames will not wait for frames if none are 
+     * available, and f will not be invoked.  If \p timeout is -1 (the 
+     * default), rx_frames will block indefinitely until frames are 
+     * available.  If \p timeout is positive, it indicates the number of
+     * milliseconds to wait for a frame to become available.  Once the
+     * timeout has expired, rx_frames will return, f never having been 
+     * invoked.
+     *
+     * \p f will be called on each frame that is available.
+     * \p f returns a bit mask with one of the following set or cleared:
+     * 
+     * data_handler::DONE -  return from rx_frames now even though more frames
+     *                       might be available; otherwise continue if more 
+     *                       frames are ready.
+     *
+     * \returns EB_OK if at least one frame was received
+     * \returns EB_WOULD_BLOCK if \p timeout is 0 and the call would have blocked
+     * \returns EB_TIMED_OUT if timeout occurred
+     * \returns EB_ERROR if there was an unrecoverable error.
+     */
+    result rx_frames(data_handler *f, int timeout=-1);
+
+    /*
+     * \brief Returns maximum possible number of frames in buffer
+     */
+    unsigned int max_frames() const { return d_using_tpring ? d_frame_nr : 0; }
+  };
+
+};  // namespace vrt
+
+#endif /* INCLUDED_VRT_SOCKET_RX_BUFFER_H */
diff --git a/vrt/vrt.pc.in b/vrt/vrt.pc.in
new file mode 100644
index 000000000..0f8cb938b
--- /dev/null
+++ b/vrt/vrt.pc.in
@@ -0,0 +1,11 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: vrt
+Description: Host implementation of Virtual Radio Transport (VITA-49)
+Requires: 
+Version: @VERSION@
+Libs: -L${libdir} -lvrt
+Cflags: -I${includedir}