Troubleshooting Tips for ttyS0 problem

[Pete <peteracole@bigpond.com>]

Hi all,

I need to get some troubleshooting tips for finding out what is causing
my serial port not to function in Sarge.

If I plug a modem in, boot off an old DOS 6.22 floppy, and run Modem Dr,
it verifies that it can communicate successfully with the modem with not
one single error.

However, if I boot into Sarge, and try to talk to it with Minicom, it
always stays offline and I never receive any responses from the modem.

I need to get this functioning so I can get my UPS running as this is my
mail server which runs 24x7.

I have tried purging and reinstalling setserial, but this didn't help.

I'm running a custom 2.4.27 kernel and have also tried the standard
2.4.27 and 2.6.8.1 kernels with the same results.

As far as hardware goes, it's a Via EPIA V10000 mainboard and the UPS
I'm trying to communicate with is a Sola 330, which used to work fine on
my old mail server with the same cable and same software (NUT).

The modem is a Spirit 33.6K.

What else can I do to narrow down what's interfering with the serial
port?

Any tips would be very greatly appreciated.

Thanks in advance,

Pete