The Telecom Digest for December 10, 2010
Volume 29 : Issue 333 : "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
email.
===========================
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: Thu, 9 Dec 2010 09:49:55 -0800 (PST)
From: Lisa or Jeff <hancock4@bbs.cpcn.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: Question about an old scrambler phone
Message-ID: <2a2a0895-c61d-43cc-8ab1-560298fcb3f2@h22g2000vbr.googlegroups.com>
On Dec 8, 7:38 am, bon...@host122.r-bonomi.com (Robert Bonomi) wrote:
> One of the simplest forms of a 'scrambler' simply frequency-inverted
> the audio input. basically, use the audio to AM modulate a circa
> 4kHz 'carrier', and send only the the lower sideband over the
> wires..
When the Bell System introduced overseas communications via radio,
they included frequency shifting as a privacy measure. It was more
designed to prevent inadvertent evesdropping as opposed to stringent
security. They said a person with excellent hearing and skill could
listen the discern the conversation, and of course constructing a
descrambler would not be hard to do.
It's written up in the Bell Labs history.
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
'comp.dcom.telecom'.
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
Telecom Digest
43 Deerfield Road
Sharon MA 02067-2301
781-784-7287
bill at horne dot net
Subscribe: telecom-request@telecom-digest.org?body=subscribe telecom
Unsubscribe: telecom-request@telecom-digest.org?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
organization.
End of The Telecom Digest (1 messages)
|
| |
or 