Hayes compatible modems on 3620s with 8.0 from the console serial port

[munoz@oberon.com (Richard A. Munoz)]

   Date: Sun, 2 Jun 91 11:19 EDT
   From: pan@ATHENA.PANGARO.dialnet.symbolics.com (Paul Pangaro)

   Has anyone hooked up a configuration with Hayes compatible modems on
   3620s with 8.0 from the console port? We have a 3620 that worked fine
   with the Mailer with the same modem and serial port under 7.2 a few
   months ago, but cant get it to work now. (We've blown off the 7 worlds
   and cant try it that way conveniently). The modem is still fine (works
   on other machines), and other consoles have been tried with no luch; I
   think the only thing we havent tried is swapping boards in the 3620,
   which is very troublesome (no spares handy). I wondered if anyone has
   made this configuration work, which would mean that I have to try what
   is troublesome to see if the i/o hardware has gone bad just recently.
   All advice welcome, thanks.  (Come to think of it, the tape drive
   started acting up at the same time, but that symptom is that is does not
   always "see" the tape drive, does not select (no light or head reset),
   but then you flip the lever to hold the tape in, it finds it again, but
   only for a single read ---- this sounds unrelated, no?)

[This is from memory, so I may have the details wrong.]  Several
months ago a bug was found in the NBS Console serial stream support
software. It turns out that when the Console port was used (on an NBS
machine) for bidirectional traffic, the input and output streams got
their data confused. If I remember correctly, during birectional data
flow, the output stream would place three "output" bytes into the
input stream for every "input" byte retrieved (via tyi) thereby
corrupting the input stream. As of December, 1990, developers at
Symbolics did not yet find what was causing the problem.  Perhaps
since then they've gotten closer to figuring it out.
 
 - Rick