Provided by: ax25-tools_0.0.8-13.1ubuntu1_i386 bug

NAME

       soundmodem - amateur (AX.25) packet radio network driver for soundcards

SYNOPSIS

       #include <linux/soundmodem.h>
       #include <linux/hdlcdrv.h>

DESCRIPTION

       The  driver  currently  supports  both 1200 baud AFSK and 9600 baud FSK
       (G3RUH  compatible)  using  a  standard  SoundBlaster   compatible   or
       WindowsSoundSystem  compatible soundcard. The whole decoding is done in
       software, so you definitely do not want to use  it  on  a  386SX  class
       machine.

KEYING THE TRANSMITTER

       Soundcards  do  not  have a DC coupled output that could serve as a PTT
       signal. So there are basically for possibilities for  obtaining  a  PTT
       signal.     Sample    schematic    diagrams    can    be    found    on
       http://www.ife.ee.ethz.ch/~sailer/pcf/ptt_circ/ptt.html.

   VOX circuitry
       A simple VOX circuitry that detects output signals at the output of the
       soundcard  can  be  used,  especially  as it can be built with a single
       transistor plus a few passive components and  typical  soundcards  have
       strong output signals.

   Parallel Port
       A  parallel  port line can also be used to signal PTT. If selected, the
       PTT signal is output on the DATA0 line and DCD is output on  the  DATA1
       line.

   Serial Port
       A  standard serial port (8250, 16450, 16550) can also be used to output
       PTT. PTT is output on RTS and TxD, while DCD is output on DTR.

   MPU401 MIDI Port
       The MIDI port is basically an asynchronous serial  interface  and  thus
       cannot  output a straight DC level, however it may be used if connected
       through a retriggerable monoflop with about 15ms pulse  duration.  Note
       that  only  newer  SoundBlaster models have a genuine MPU401 MIDI port.
       The older SB MIDI port cannot be used.

IOCTL CALLS

       The ioctl calls follow the implementation in the hdlcdrv.

       SMCTL_GETMODEMTYPE
              returns the  modem  type  (i.e.  SBC1200,  SBC9600,  WSS1200  or
              WSS9600)

       SMCTL_SETMODEMTYPE
              sets the modem type. Only superuser can do this.

       SMCTL_GETMIXER
              returns  the  mixer type and the contents of the specified mixer
              register.

       SMCTL_SETMIXER
              sets the specified mixer register, if the specified  mixer  type
              matches  the  mixer type of the soundcard. Only superuser can do
              this.

       SMCTL_DIAGNOSE
              returns the contents of the diagnose buffer, which  is  used  by
              smdiag to display the eye and oscilloscope diagrams.

       SMCTL_GETDEBUG
              return some debugging values. Not always available.

SEE ALSO

       baycom      (9),     soundmodem     (9),smdiag     (8),smmixer     (9),
       linux/drivers/net/hdlcdrv.c,

AUTHOR

       soundmodem   was    written    by    Thomas    Sailer,    HB9JNX/AE4WA,
       (sailer@ife.ee.ethz.ch).