Provided by: ax25-tools_0.0.8-13_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).