[Techtalk] ISA PNP modem help

Dave North dave at timocharis.com
Mon Aug 5 21:36:23 EST 2002


Ain't nobody answering so I'll give it a shot.

> I am configuring a couple of Linux (formerly Windows) boxen for a
> friend.  I always use an external modem on my desktop and a PCMCIA modem
> in my laptops, so I've never run into a problem with a modem before.

I've generally run internals, favoring ISA when I can (for a reason we'll
get to).

> I do know about setserial, but I have to somehow know which serial port
> they are assigned to in order to use that, or worse, I need to know how
> to assign them to a given port and memory address range.

That's unlikely. Here's what normally worked for me:
	First, I don't understand all this crap so I won't pretend to. Ak
and I worked through ISAPNP once, made it work, and I promptly forgot the
whole thing.
	What I did was make sure I got modems with jumper switches on
them, and set the com/irq in hardware. For example, windows always seemed
to work best with the com2/irq3 setting, and I found that normally worked
fine in linux as ttys1.
	Just because you don't think you have to use the jumper doesn't
mean it isn't there. Many of the ISA modems had a jumper setting for "use
jumpers/don't use jumpers" and, of course, when you set that switch,
magically you have hardware control!
	So look for those jumpers. They're usually there; if not, we'll
probably have to figure out the isapnp thang -- unless you haven't tried
wvdial (you have, haven't you?)

The other thing to check for is whether or not your serial port is
activated in bios. This is again something I don't understand in any
detail that would allow me to type hex numbers, but with some bioses if
you have the serial port activated, the isa card won't be able to claim
that port for itself, and you either get a conflict or a nonworking modem
with no comment.
	So maybe the easiest thing to do is, with your current setup,
check the bios and see if you can turn serial port 2 off and see what
	I cannot stress too much how valuable jumper switches on an isa
modem can be...

> Both boxes are running Red Hat Linux 7.3.

The really bad news is, I haven't set up a modem for a loooong time, and
this is all flying from crappy memory.

Should you happen across one of the excellent Jaton Modulators, I know
_exactly_ how to set it up. Big help, huh?


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