Re: [Discuss-gnuradio] About tunnel.py again

[Eric Blossom]

On Tue, May 25, 2010 at 10:03:32AM -0700, Juan Quiroz wrote:
> I'm trying to connect two computers  using tunnel.py example but it fails 
> with a message uOBBBB, I'm working with Ubuntu
> 9.04, openSUSE 11.1 and GNU radio 3.2.2. Everything was fine when I did
> it with GNU radio 3.1.3 and both computers with openSUSE 11.1Please can 
> somebody tell me what BBBB means?
> 
> JhonQ

A quick look at the code reveals that it means that the transmitter
has backed off because it detected carrier.

        while 1:
            payload = os.read(self.tun_fd, 10*1024)
            if not payload:
                self.tb.send_pkt(eof=True)
                break

            if self.verbose:
                print "Tx: len(payload) = %4d" % (len(payload),)

            delay = min_delay
            while self.tb.carrier_sensed():
                sys.stderr.write('B')
                time.sleep(delay)
                if delay < 0.050:
                    delay = delay * 2       # exponential back-off

            self.tb.send_pkt(payload)


Try changing the carrier threshold using the -c command line option.

Eric