This chapter describes commands that are specific to modem type links. These commands apply to the currently active link, and are only valid if the currently active link has type modem.
set modem device devname
Modem links operate over serial ports. This command tells mpd
which serial port to use for this link, and is required.
devname should be the pathname of a serial
set modem var $variable string
Pre-sets the chat script variable
$variable to contain
chat for more information
on chat variables.
set modem speed speed
This commands sets the initial serial port speed when opening the serial device, e.g., 9600, 57600, 115200. Note that you can always change the serial port speed later from within the chat script.
set modem script connect-script
This command tells mpd which chat script to run in order to initiate
a PPP connection for this link. The
should correspond to a label in
mpd.script. Mpd will jump
to this label after opening the serial port device. If
connect-script is not set, then the chat phase
of the connection is skipped (e.g., if you have a direct null modem
set modem idle-script idle-script
This command tells mpd what to do with the serial port when the link is
not connected. If no
idle-script is set, then mpd will
leave the serial port closed when not connected. Otherwise, when the
link is disconnected mpd runs the
script. If this script returns
failure, then mpd
restarts the script.
Otherwise, (i.e., if it returns
success) mpd examines the
contents of the
$IdleResult chat variable to decide what to do
next. If it equals
answer then mpd will assume that an incoming call has been
answered and immediately enter PPP negotiation. If it equals
ringback then mpd will close the serial port, reopen it,
and initiate an outgoing connection normally (i.e., using
$IdleResult contains anything else or is not set, then
mpd acts as if
failure had occurred and simply restarts
set modem watch +/-signal ...
Mpd normally tracks the carrier detect signal on the serial port
and drops the connection when this signal is lost. You can disable
this behavior with
set modem watch -cd. Also,
mpd can do the same thing with the DSR signal, though the default
is to ignore DSR. To enable watching of the DSR signal, use
set modem watch +dsr.