[aprssig] linux sound modem help

Wes Johnston aprs at kd4rdb.com
Tue Nov 30 17:48:06 EST 2004

I'm trying to get the linux soundmodem working (for xastir), and each time I try
to run "soundmodem &" as root, I get

sm[procID]: ioctl: TIOCSETD: Invalid argument (22)

I started by installing ax25 module in the mepis 2.6.7 kernel (
 for those of you looking for the easy way!)

I then installed the ax25 support programs... apt-get install ax25*

the sound modem, apt-get install soundmodem

then ran soundmodemconfig.  The /etc/ax25/soundmodem.conf file is as follows:
<?xml version="1.0"?>
  <configuration name="SndModem">
    <channel name="Channel 0">
      <mod mode="afsk" bps="1200" f0="1200" f1="2200"/>
      <demod mode="afsk" bps="1200" f0="1200" f1="2200"/>
      <pkt mode="MKISS" ifname="sm0" hwaddr="KD4RDB-2" ip=""
netmask="" broadcast=""/>
    <chaccess txdelay="150" slottime="100" ppersist="40" fulldup="0"
    <audio type="soundcard" device="/dev/dsp" halfdup="0"/>
    <ptt file="/dev/ttyS0"/>


My axports file looks like this:
# /etc/ax25/axports
# The format of this file is:
# name callsign speed paclen window description
aprs	KD4RDB-2	1200	255	7	Soundmodem

To make matters more confusing for me, I have a machine sitting here on my
desktop with the same configuration (thanks to kc4pl) and it's working fine.  I
have duplicated everything in it I can think of.

Where did I go wrong?

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