Modem / Unix / USR Failed to help (surprise !)

[Gary Major]

OK, I put this one to USR who promptly said it was nothing to do with
them - so can anyone here suggest anything.

We have 3 x USR Sportsters (Flash & 33.6 models) which allow people to
dial into our Unix (Linux) machine. Usually (9/10 times) this works
fine, but sometimes, the guys in the field dialing in manage to make a
mistake loggin in, thus they get kicked off by the Unix machine, or
crash their laptop (Win 95 Dial-up networking).

WHen this happens, the USR appears to reset, but the no other
connections can made to that modem. What happens, is that the OH
light clicks in and then out again repeatedly until the incoming
connection times out, usually about 30 seconds or so. Whilst this is
happening, both Send and Receive stay permanently lit, with no
flickering.

After the call has terminated, the modem is left with the following
lights on SD RD TR CS (AA is also set by default) normally we would
expect TR CR + AA to be on.

The modem is then effectively useless until it is powered off and then
back on again. We can acces the modem from the Unix machine and issue
AT commands etc. All the factory restes and changes we can think of
do not work.

We suspect this may be flow control related, with the Unix machine is
usually what kicks them off. We've tried S13=1 and suchlike, and as
best we can, changed all the flow control stuff to software xon xoff.

Any Ideas Please ???

Regards
Gary Major