modem control on DEC DHQ11/DHV11

[Alan M. Steele]

    Does anyone know about problems with the DHV11 driver in 4.3BSD unix?
I have been told that it is a horrendously buggy driver that no one
has bothered to fix.  Specifically, it seems to have a lot of problems
with modem control.

    We have a MicroVAX II with a DHQ11 serial board and three modems
(one of them is a Trailblazer) connected for uucp purposes.  We are
running BSD4.3 with the standard DHV11 driver.  The problem we have
encountered is that after a uucp connection closes, the DHQ drops DTR
for the standard few seconds (I don't remember exactly how many) and then
raises DTR normally.  With a few seconds after it raises DTR, there is
a quick flash of signals (I have looked at the signals with a breakout
box) and then DTR drops again and stays low, wedging that dialin line.

    As a temporary fix, we found that killing the getty process on the
wedged tty line somehow resets the line to normal.

    Does anyone know of patches for the 4.3BSD DHV11 driver which fix
these problems with modem control?  Is there some other workaround?
(Perhaps modifications to getty?)

    Please respond via mail -- I will collect answers and post a summary.

-Alan Steele
 MIT EECS Educational Computing Facility
 neptune at fenchurch.mit.edu      ...!mit-eddie!neptune