Pyramids and Telebit TB+ modems

[David Macklem]

This question is probably asked everytime a Pyramid site hooks up a
Telebit Trailblazer but, anyways, here goes.

I have a Nixdorf Targon 35 running TOS3.3 (I don't know the
corresponding Pyramid version number but the att side is SVR2 not SVR3
and the uucp is not HDB).

When I first hooked up Telebit TB+ modems to my Pyramid, transfers over
these modems via uucico at 9600 baud caused disturbing messages on the
console:  "itp41: port0 uart overrun".  (ipt41, port 0 was the port
being used by the uucico process). Eventually the uucico process would
die.

I was able to fix this (for most transfers) by setting ITPHOWOFTEN=2 in
the kernel and re-making it. (No, I don't have source). This has solved
the problem for our mail and news feed.

However, currently, one of our uucp neighbours is trying to send large
files (>1meg) to our machine and these annoying messages are
re-appearing. This time the screwed up uucico process sometimes crashes
the Pyramid. If the system does not crash but the uucico process dies,
further uucico transfers to/from other sites (which would use the same
itp if not necessarily the same port) exhibit the same behaviour. The
machine has to be powered down and back up again to get it back to a
normal state. (Our users like this :-)).  It's almost as if the uart
overruns are screwing up the itp so badly that it can't recover.

As far as I can tell, the modem registers (at both ends) are set
properly (hardware flow control only, g-protocol spoofing, 8bits, no
parity, etc..) and as mentioned, we don't have any trouble with our
full news feed or mail. Admittedly, the news batches come in files that
are <= 50k but there is still a total of about 3meg per day. I have
told this offending neighbour not to transfer files > 100k but I'm
hoping there is a better solution.

Has anyone out there seen this before and, more importantly, did you fix
it? If so, how?

I'm grateful for any help.
-- 
David Macklem 		Nixdorf Computer Canada, Limited
davidm at nixtor
uunet!jtsv16!geac!nixtor!davidm