[wplug] Serial killer

[Vance Kochenderfer]

Thanks to everyone for the responses.  I'll try to take them in turn:

IRQ sharing - I don't believe there would be anything else using the
same IRQ.  Would /proc/interrupts tell me this?  They haven't added
or removed any hardware, so there should be no reason for IRQs to
start shifting around...

Serial cable - Yes, it's a real serial cable with flow control lines,
has worked fine for ages.  It's just possible that it somehow went
bad, but I consider that a long shot.

Power - Everything is plugged in and turned on.  :)  We get lights
on the modem (even the RX/TX lights flash when trying to talk to it)
so that looks OK.  I had them check the phone line, too.

Lightning - This was one of my later questions, but they didn't
have any storms around that time.  It's still possible that some
kind of discharge fried something, though.

Loopback test - You're right, it's too technical for the people who
have access to the hardware to try this.  It'll have to wait until
I'm back visiting in a few weeks.

Baud rate - This is my last real question mark.  The PC's interface
is set at 115200 and AFAIK has always been.  It was my impression
that all modems made in the last decade or so will set their
interface speed automagically.  Anyone ever experienced their
modem randomly changing its interface speed for no apparent reason?

This whole thing is just baffling, because if there's one thing
I've found to be rock solid under Linux, DOS, and even Windows,
it's serial ports.

I'll have to try out some of the more involved hardware tricks when
I'm visiting again.  Thanks for the suggestions.

Vance Kochenderfer        |  "Get me out of these ropes and into a
vkochend at nyx.net          |   good belt of Scotch"    -Nick Danger