Revision 3 as of 2011-04-30 02:23:34

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Joey, NV0N, has been working on finding the right configuration for USB Sound Modems like the Tigertronics SignalLink USB. Below is a work in progress under Natty. Feel free to edit this page if you have success.


This setup requires these packages:

  • libax25 - library for hamradio applications
  • ax25-apps - AX25 ham radio applications
  • ax25-tools - AX-25 tools
  • ax25-xtools - AX-25 tools (X versions) - optional
  • ax25spyd - AX.25 traffic analyzer, dumper and spy daemon
  • soundmodem - Sound Card Amateur Packet Radio Modems
  • rigctl - Rig Control programs
  • node - ham radio node (digipeter) application

Configuration Files

Soundmodem config

From /etc/ax25/soundmodem.conf


  • the IP address can be arbitrary for your testing (in fact, you can just leave it as is)
  • replace the NV0N callsign with yours
  • replace the hamlib configuration with yours. (123 is a Yaesu FT-897)

<?xml version="1.0"?>

<configuration name="siglink"><channel name="Channel 0"><mod mode="afsk" bps="1200" f0="1200" f1="2200" diffenc="1" filter="df9ic/g3ruh" inlv="8" fec="3" tunelen="32" synclen="32"/><demod mode="afsk" bps="1200" f0="1200" f1="2200" diffdec="1" filter="df9ic/g3ruh"/><pkt mode="MKISS" ifname="sm0" hwaddr="NV0N-8" ip="" netmask="" broadcast="" file="/dev/soundmodem0" unlink="1"/></channel><chaccess txdelay="300" slottime="100" ppersist="64" fulldup="0" txtail="30"/><audio type="alsa" device="plughw:2,0" halfdup="1" capturechannelmode="Mono"/><ptt file="/dev/ttyUSB0" hamlib_model="123" hamlib_params="-s 4800"/></configuration></modem>


The standard naming convention for soundmodems is sm0

# /etc/ax25/axports
# The format of this file is:
# name callsign speed paclen window description
sm0     NV0N-8  1200    255     2       145.090 MHz (1200  bps)


# /etc/ax25/ax25d.conf
# ax25d Configuration File.
# AX.25 Ports begin with a '['.
[NV0N-8 via sm0]
NOCALL * * * * * * L
default 1 10 3 300 10 5 -       root    /usr/sbin/node node %d %s

startup script

This is the startup script (I call it Must be run as root/sudo. Advice is to run these manually the first few times until you get no errors.

# start ax25 with the soundmodem driver using the port
# defined in /etc/ax25/axports
/usr/sbin/soundmodem /etc/ax25/soundmodem.conf -R -M >/dev/null 2>/dev/null&
sleep 1
# TNC Parameters txd, persist, slottime, txtail are done by
# soundmodemconfig and stored in soundmodem.conf
# this adds a route to our soundmodem
/sbin/route add -host dev sm0
# route to the rest of the netrom IP capable nodes
/sbin/route add -net netmask gw dev sm0
sleep 1
# listen for various incoming connects like PMS, node, etc.
# (MUST first be configured in /etc/ax25/ax25d.conf)
sleep 1
# listen for stations heard

At this point you should be at a command line and can run

axcall sm0 callsign

where callsign is your local BBS.