An typical inittab entry for mgetty looks like this (on
SystemV-style OSes):
<tt>:rlevel:<respawn|off>:/usr/local/sbin/mgetty [options] <device>
where ‘tt’ is a short form of the ‘device’ name, used by
init and who for internal purposes. Usually this is
something like ‘S0’ or ‘2A’ or so.
‘rlevel’ specifies the runlevel that the command in the fourth field
is run at, this may be ‘23’ or ‘56’ or so, look at man
init and the existing /etc/inittab on your system.
The next field tells init whether that entry is active
(respawn) or not (off), and the fourth field specifies the
full path of the program to run.
The following options are available for mgetty:
‘-x <level>’ sets the debugging level. This is very important
for diagnosing problems, as with higher levels, mgetty will write
very detailed informations about its internal workings to its log file.
‘-s <speed>’ sets the port speed. If not specified, the default
from policy.h, (definition DEFAULT_PORTSPEED) will be used.
‘-k <space>’ sets the minimum number of kbytes required on the incoming FAX spool directory. If there isn’t this much space in the spool directory, the connection is terminated. The default is 1 megabyte.
‘-m 'expect send ...'’ sets the modem initialization sequence.
‘-r’ for direct lines (no modem chats are done)
‘-p <login prompt>’ sets the login prompt (various escapes are allowed)
‘-n <rings>’ sets the number of RING messages to expect
before sending ATA to answer the phone. Default is one RING.
‘-R <sec>’ tells mgetty to enable “ring-back” or “ring-twice” mode. This means that mgetty won’t pick up a call immediately, but the caller has to hang up after the first ring, and call again in the next <sec> seconds.
‘-i /etc/issue’ specifies the issue file to display before prompting for login.
‘-S <fax_document>’ specifies the document(s) to send to
polling fax machines (full path required). <fax_document> has to be
in G3 format (as for sendfax), or a text file listing G3 fax files
(one file per line).
A sample entry in /etc/inittab might look like this:
F1a:23:respawn:/usr/local/sbin/mgetty -x 3 tty2a
For a more detailed explanation of all the options, please look into the mgetty(1) man page.