[comp.dcom.modems] Telebit TrailBlazers and UUCP

dale@lamont.LDGO.Columbia.edu (dale chayes) (11/18/87)

We are using Telebit TrailBlazers with Berkley 4.3 uucp to link our
lab network with our geophysical research vessel (Robert D. Conrad.)
The TrailBlazers have version 3.0 EPROMS. We set up a reasonable
test period in the lab, and then over a local (very noisey) phone 
line and got good results (which I reported a couple of weeks ago.)

We are now running between the lab and the ship (at sea) through 
an INMARSAT satelite link and having intermittent problems.  In general,
we see "pkcget: alarm n" and eventually the link fails.  We are sucessfully
transfering files, but the data rate is highly variable, and it is
not reliable enough to let it run automagicly.

My present hypothesis is that the extra delay induced by the sat. link
is causing time outs....but I haven't been able to sleuth out what to 
change.

I have spent hours looking at the code, (and seconds reading the profuse
comments (:-)) and would really like to talk to someone who is familiar with
uucp. 

	Dale Chayes
usmail:	Lamont-Doherty Geological Observatory of Columbia University
	Route 9W 
	Palisades, N.Y.,   19064
voice:	(914) 359-2900 extension 434
fax:	(914) 359-6817 (all kinds)
usnet:	...philabs!lamont!dale
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are we having fun yet?....

pete@octopus.UUCP (Pete Holzmann) (11/18/87)

In article <222@lamont.LDGO.Columbia.edu> dale@lamont.LDGO.Columbia.edu (dale chayes) writes:
>We are now running between the lab and the ship (at sea) through 
>an INMARSAT satelite link and having intermittent problems.  In general,
>we see "pkcget: alarm n" and eventually the link fails.  We are sucessfully
>transfering files, but the data rate is highly variable, and it is
>not reliable enough to let it run automagicly.

We just received our Trailblazer, running firmware level 3.01. I can also get
the link into a 'pcget: alarm 1' infinite loop. It almost always happens if
I force the serial line between my cpu and the modem to lose a few characters
(either by overrunning the FIFO in the cpu, or by glitching the serial line
with a breakout box.

Since this doesn't happen if I'm not running the Trailblazer's 'g' protocol
spoof, I'm ready to guess that there's a bug in the modem's error recovery
support. I'm working hard on this right now! 

Has anybody else seen this problem?

Pete

-- 
  OOO   __| ___      Peter Holzmann, Octopus Enterprises
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