Can't Query External Serial Modem

Tommy Trussell tommy.trussell at gmail.com
Tue Mar 13 14:25:20 UTC 2007


On 3/12/07, Bernard Helyer <b.helyer at hotmail.com> wrote:
> >The send/receive lights should flash with every keystroke, so my first
> >thought is that either the cable is bad, wired wrong, or you're not
> >pointing at the right serial port.
>
> Well, as I said, wvdialconf makes the lights turn off and on when querying
> /dev/ttyS0, and that's what both minicom and HyperTerminal (com1) are
> pointed to.

That's a good start... but the problem is, if the cable is wired for
another type of device, you may just be seeing the handshaking lines
going high and low, making the lights change. If you have not found
any serial setting that makes the Tx and/or Rx lights flash with every
keystroke, I will be further convinced that your cable wiring is
suspect. The cable may not be "broken" per se, it may just be wired
for a different thing. For example, here's your description

>(the 56k one that plugs into the modem is
> round and small to a 9pin, and was the one the previous owner used I think)

This COULD describe a cable for a Macintosh (their serial ports are
round) but having the 9-pin female connection on the other end would
be backwards. (You haven't mentioned that you're using an adapter.) If
you have a manual for the modem, it might indicate the proper
connections, which you could confirm with a continuity tester.

I just did a couple of Google searches, and found a few reviews. I
found a couple of red flags -- for example the modem apparently was
marketed with some telephony features in their Windows drivers
(something about working with your sound card), which MAY mean that
it's not actually a standard serial modem. Apple made one like that --
it was actually an external DSP that required driver software on the
Mac. PLUS there are numerous support board postings where folks were
distressed that there was no driver for it when they upgraded to
Windows XP.

Oh and I just found your forum thread
http://ubuntuforums.org/showthread.php?t=376327 so I'm reading it to
see what else you've tried. Yeah... I see. Hmm...

We can't be sure it's the right cable, AND we can't be sure it's
actually a serial modem. Maybe that's where the "Fun" comes from in
its name. ;-)

SO maybe you want to tackle the winmodem again... but bad news...
another Google search turned this up:
http://www.ubuntuforums.org/showthread.php?t=198730 -- apparently the
linux driver that used to work won't work with newer kernels (this was
written for Dapper). So I'd be afraid to recommend it if it might be
touchy.

Have you been through the steps at http://linmodems.org/ ? I gather
that there are still some winmodem chipsets that are completely
unsupported.

Here's what I did in one case -- I went to a computer repair shop and
paid them a few bucks for a Lucent winmodem they had pulled from a PC.
 I knew I could find a driver for Lucent.... and it works OK...
HOWEVER at this point I'm tempted to give up on it again and buy a
cheapo serial modem from geeks.com -- they still have two models
available, and each costs less than $10US. I want to ditch the
winmodem because the system has an older Ubuntu on it and I know I'll
have to deal with an upgrade, and if I can find an ACTUAL working
serial modem it will be easy.

Sorry my response has become disjointed -- I just had a bunch of
interruptions (my workday started) so let me know how you fare...




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