vnend@phoenix.Princeton.EDU (D. W. James) (10/18/90)
Yesterday(!!) I wrote:
)Princeton has a bank of 4 Telebit T2500's to service its UUCP
)connections. A few of those are 2400 baud no-name modems that
)seem to be happy connecting to just about any other 2400 baud
)modem, but that die when they try to connect to the Telebits.
)One of them is mine, so I'm a little interested in the problem.
)What happens is that my (for example) modem calls in, the Telebit
)goes through its attempts to connect using PEP and some other
)protocals, then finally starts sending a 2400 carrier. At that
)point my modem starts to handshake, then hangs up abruptly. We
)watched the telebits today: the carrier detect light comes on on
)them, but by that time my modem has disconnected. The CD light on
)my machine never comes on, but the recieve data light flashes.
)I get the same results calling a v32 machine. Machines that try
)MNP don't faze it. The Telebits do not have MNP turned on.
)If anyone else has run into this, and found a fix other than
)buying a new modem, I and a few others would like to hear it.
)Sorry if this has been brought up here before, I've only been reading
)this group for a couple of weeks.
First of all, I (stupidly) forgot to note that we have already
ruled out timeout of either the modem or uucico as the culprit. Thanks
to all of you that pointed that out as a possible answer.
Credit goes to Kenneth K.F. Lui <tempest@walleye.ecst.csuchico.edu>,
who was the first to send me the correct work-around for the problem, which
was in my mailbox about an hour after I posted the question. He suggested
padding the end of the dialling string with enough comma's to get my
modem to not even start looking for the carrier until after the Telebit
had started sending the 2400 baud carrier. While my modem seems to ignore
PEP and the next two tones that are sent, this seemed to be a reasonable
thing to try, so I did.
Bang, first time and we are in. Took a little more playing with
it to get it to account for extra rings (the Telebits usually pick up
on the first ring, but not always) but things are running smoothly now.
For those who are interested, it seems that 26 seconds is a good delay.
Judging from the way the two modems worked when side-by-side, it
looks as if there is something in the tones the Telebit sends when it is
first starting 2400, though it could also be something at the end of the
carrier it tries just before that (V.32). In any event, we've got it
working here. The technically curious may want to look and see what it is
that the telebit is sending that is causing it.
The net comes through again. Time from posting to connection was
between 5 and 6 hours. Thanks to all of you that responded.
David James
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