From: rick@ee.uwm.edu (Rick Miller - Linux Device Registrar) Subject: [ANSWERS]: Serial Comm Problems Date: 5 May 1993 15:45:27 GMT
sohail@rhonda.jsc.nasa.gov writes:
>I have SLS 1.0 and then 0.99pl8 loaded. I have a normal I/O card with two
>serial ports configured as COM1 and COM2 (IRQ4 and IRQ3 respectively). In
>addition to that I have TWINCOM 14.4 internal modem sitting as COM4 (IRQ 3).
>I use COM1 for a MouseSystems serial mouse and COM4 for the internal modem.
>COM2 although configured is not in use at this point. I have the mouse
>configured as /dev/ttyS0 and modem as /dev/ttys3.
>
>ARE THESE THE CORRECT DEVICES TO USE FOR THE RESPECTIVE COMM PORTS ???
Using /dev/ttyS0 is correct for your mouse.
You should use /dev/cuaS3 for your modem. You probably don't yet *have*
this device though, so you'll need to do like so:
mknod /dev/cuaS3 c 5 66
and use /dev/cuaS3 when calling out. You should use /dev/ttyS3 for
setting up dial-in through the same modem though. Two names for the
same device... one for dial-IN, the other for dial-OUT. This is so
the kernel can do the locking for you (to prevent you from stomping
on some poor luser's dial-up login).
DON'T USE /dev/ttys0 (lowercase "s") FOR SERIAL LINES.
That name *should* belong to the slave-tty for /dev/ptys0.
[...] How does linux detects the ports and manages two ports with
the same interrupt (i.e. COM2 and COM4) ???
It DOESN'T. That's a *hardware* function, and should only be done with
multi-port boards. (Some folks have even modified their serial boards.)
Rick Miller <rick@ee.uwm.edu> | <ricxjo@discus.mil.wi.us> Ricxjo Muelisto
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