doug@csd4.milw.wisc.edu.UUCP (11/19/87)
A while back (3-4wks) there was some discussion of a problem somone
was having with line noise (specifically {) on there 1200 baud lines.
We are experiencing a similar problem with here where we get noise in
the form of { on our 1200 baud dial-up lines. This problem came
up after the campus switched to a new phone switching system.
I didn't save any of the articles at the time and now wish I had.
I would appreciate it if someone could send me a summary of possible
explanations and/or the original articles. I specifically remember
one where there was a problem with the phone company and one with the
modem.
Any help would be appreciated. Thanks
Doug Tiarks
UW-Milwaukee Computing Services Div.
Internet: doug@csd4.milw.wisc.edu
UUCP: {uwvax, uwmacc, ihnp4}!uwmcsd1!dougkoko@uthub.UUCP (11/20/87)
What a coincidence. When the University of Toronto had a new telephone
system installed within the past year, I started experiencing the noise
that you described -- mainly "{}ir~" characters during mild spells, or
almost any characters during heavy spells. Supposedly Bell Canada has
been trying to trace the problem, but acknowledges that the problem is
caused by their new digital switching equipment. I think that the noise
may be caused by the random dropping of digital samples perhaps when the
total load on the switching system is heavy. (I have noticed that only
the 978 numbers are noisy, and only when an audio signal is present,
and that there is more noise, on average, during the day, when one expects
telephone traffic to be heaviest.)
In any event, if you experience noise, then complain! The problem
will never get corrected if you don't let anyone know that it exists!
I, along with other users, complained in the past until Bell fixed the
problem. However, a month ago the problem cropped up again. I have
complained, but so far there have been no results.stevens@hsi.UUCP (Richard Stevens) (11/23/87)
One interesting point: I used to use a dumb terminal at home with
a RV 3451 modem at 1200 baud. The VAX answering the phone call also
had RV modems, so they were using the RV 1200 baud protocol between them.
Everything was perfect for 3 years - rareley (if ever) did I ever see
any phone noise on the lines.
Then recently I switched to an AT&T 3b1 (the UNIX PC) with an internal 1200
baud Bell modem. Now on almost every call I see the spurious characters
(usually the "{" and "i" characters), sometimes a few per call,
sometimes a few per minute.
Richard Stevens
Health Systems International, New Haven, CT
{ uunet | ihnp4 } ! hsi ! stevens