The Telecom Digest for November 22, 2010
Volume 29 : Issue 315 : "text" Format
Messages in this Issue:
====== 28 years of TELECOM Digest -- Founded August 21, 1981 ======
Telecom and VOIP (Voice over Internet Protocol) Digest for the
Internet. All contents here are copyrighted by Patrick Townson and
the individual writers/correspondents. Articles may be used in other
journals or newsgroups, provided the writer's name and the Digest are
included in the fair use quote. By using -any name or email address-
included herein for -any- reason other than responding to an article
herein, you agree to pay a hundred dollars to the recipients of the
Addresses herein are not to be added to any mailing list, nor to be
sold or given away without explicit written consent. Chain letters,
viruses, porn, spam, and miscellaneous junk are definitely unwelcome.
We must fight spam for the same reason we fight crime: not because we
are naive enough to believe that we will ever stamp it out, but because
we do not want the kind of world that results when no one stands
against crime. Geoffrey Welsh
See the bottom of this issue for subscription and archive details
and the name of our lawyer, and other stuff of interest.
Date: Sun, 21 Nov 2010 10:18:40 -0800 (PST)
From: Lisa or Jeff <firstname.lastname@example.org>
Subject: On preliminary false switchhook pulsing
I checked the Bell Labs history ("Switching, 1925-1975") to see what
was said preliminary false switchhook pulsing. There wasn't much, and
I couldn't find anything in the 1875-1925 book.
For SxS offices:
"arrangements were developed to prevent wrong numbers due to
preliminary pulses which might be falsely generated at the start of a
call when the receiver is first taken off hook. This also resulted in
the standardization of 11X service codes compared with X11 for the
Ref: "Counteracting Dialing Errors in the Step by Step System", Bell
Labs Record, January 1929, p 198.
To add long distance to an SxS office on the basis of area code (0/1)
would've been expensive due to adding senders/registers or building
out the switch train. The easier way was to add 1 as a prefix. "An
exception was the elimination of preliminary pulse detection, a
feature that was abandoned with the obsolescence of the desk stand
* * * *
I am not sure why panel switching didn't have the problem that SxS
since both systems in their early days used desk-stand (candlestick)
Unfortunately, I don't have easy access to library issues of Bell Labs
Record to study this further. I hope someday they put the record on
line; it would answer many historical questions.
Date: Sun, 21 Nov 2010 14:49:34 -0500
From: Telecom Digest Moderator <email@example.com>
Subject: Paging firstname.lastname@example.org [nfp]
Paging email@example.com: please contact me off-list.
If you prefer, my phone number is +1-339-364-8487.
TELECOM Digest is an electronic journal devoted mostly to telecom-
munications topics. It is circulated anywhere there is email, in
addition to Usenet, where it appears as the moderated newsgroup
TELECOM Digest is a not-for-profit, mostly non-commercial educational
service offered to the Internet by Bill Horne. All the contents
of the Digest are compilation-copyrighted. You may reprint articles in
some other media on an occasional basis, but please attribute my work
and that of the original author.
The Telecom Digest is moderated by Bill Horne.
Contact information: Bill Horne
43 Deerfield Road
Sharon MA 02067-2301
bill at horne dot net
Subscribe: firstname.lastname@example.org?body=subscribe telecom
Unsubscribe: email@example.com?body=unsubscribe telecom
This Digest is the oldest continuing e-journal about telecomm-
unications on the Internet, having been founded in August, 1981 and
published continuously since then. Our archives are available for
your review/research. We believe we are the oldest e-zine/mailing list
on the internet in any category!
URL information: http://telecom-digest.org
Copyright (C) 2009 TELECOM Digest. All rights reserved.
Our attorney is Bill Levant, of Blue Bell, PA.
Finally, the Digest is funded by gifts from generous readers such as
yourself who provide funding in amounts deemed appropriate. Your help
is important and appreciated. A suggested donation of fifty dollars
per year per reader is considered appropriate. See our address above.
Please make at least a single donation to cover the cost of processing
your name to the mailing list.
All opinions expressed herein are deemed to be those of the
author. Any organizations listed are for identification purposes only
and messages should not be considered any official expression by the
End of The Telecom Digest (2 messages)