Problems with serial drivers (and postscript printer)

[System Administrator]

[ I am sorry if you have seen a similar article - the previous posting
had the wrong address so I have sent a cancel message and reposted
this ]

We are experiencing some problems with the apollo (domain OS 10.2 bsd)
serial port whilst attempting to drive a postscript laser printer.

As far as we can determine the problem occurs when the postscript file
has finished its job and the printer sends a Ctrl-d back to the
computer.  At this point the computer echos two backspace's which the
printer sees as errorneous postscript, ignores further input,
timeouts, sends end of job (ctrl-d) to which the computer sends 2
backspace's and the cycle continues.

We have played about with the port settings and have echo off and even
have ctlecho off but cannot convince the serial port not to echo the
two backspace's.

We believe at this point that there is a bug in serial driver in that
there seems to be no way to turn this echoing off.  

According to our understanding if the "stty ctlecho" is set then when
we do a Ctrl-d the terminal driver quite correctly first displays ^D
and then immediatly sends 2 backspace's and spaces before terminating
the shell (or subshell).  If on the other hand the "stty -ctlecho" is
set then on sending a ^D the shell correclty does not put it on screen
so there is no need to send the two backspace's but the terminal
driver still does.

Has anyone met with similar problem or better still can anyone suggest
a soluton or see where we are going wrong.

--
Khalid Sattar                   JANET  : admin at uk.ac.exeter.cs 
Computer Science Dept.          UUCP   : admin at expya.uucp
University of Exeter            BITNET : admin%uk.ac.exeter.cs at ukacrl
Exeter, UK.                     Tel    : +44 392 264062
--
Khalid Sattar                   JANET  : admin at uk.ac.exeter.cs 
Computer Science Dept.          UUCP   : admin at expya.uucp
University of Exeter            BITNET : admin%uk.ac.exeter.cs at ukacrl
Exeter, UK.                     Tel    : +44 392 264062