[lug] external modem configuration

Doug Shaw shawd at hex.net
Wed Nov 10 11:15:17 MST 1999

>I was wondering if anyone could help me to set up my external modem. The
>modem is plugged into a serial port and using windows I
>find it under COM2. I've tried linking to the tty devices for COM1 and COM
>2 but the kppp utility still can't find the modem. Does anyone know what
>the problem might be? Is there a quick way to use linux to find out what
>device I should link to (i.e. find where the modem is)?

The first thing to check out will be to verify if you have a Windows-only
modem (affectionately referred to as "WinModems").  If so, it will not work
under Linux.

Bypassing all the user-friendly utilities, from a command prompt (xterm or
however) you can do:

	echo ATM1L3 > /dev/cua1

This tells the modem to set itself to maximum speaker volume when off-hook
(when at a dialtone).  Note that "cua1" is "cua" and the number one, not
lowercase "L."

	echo ATH1 > /dev/cua1
This tells the modem to take itself off-hook (to get a dialtone).  When you
do this, you will likely hear the dialtone through modem speaker.  Since
you have an external modem you should also be able to see the "OH" light
activated (for "off-hook").  If this works, then you've identified the
modem and can access it from Linux.  If you don't get either of these
events then you probably have a WinModem and are SOL.

If you get a dialtone, you can do:

	echo ATH0 > /dev/cua1

to hang up the modem (put the phone back on-hook).

I don't know much about kde's utilities, but if you find the modem using
the above terms then you might want to check that there is a /dev/modem and
that it is linked to /dev/cua1.

There are numerous other things that could be suggested as problems and
solutions but try these first.  My apologies if you've already established
the functionality of the modem itself under Linux.

If anything suggested here is over your head feel free to e-mail me
privately for further clarification.


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