29 Years of the Digest ... founded August 21, 1981
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The Telecom Digest for May 15, 2011
Volume 30 : Issue 121 : "text" Format
====== 29 years of TELECOM Digest -- Founded August 21, 1981 ====== |
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Date: Fri, 13 May 2011 07:20:01 -0500
From: bonomi@host122.r-bonomi.com (Robert Bonomi)
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: History Early Data transmission technical considerations
Message-ID: <0PednWQbcvFsvFDQnZ2dnUVZ_ridnZ2d@posted.nuvoxcommunications>
In article <4DCC8263.60106@frontier.com>,
Jim Bennett <ajbcommconsulting@frontier.com> wrote:
>On 2011-05-12 00:27, Reed wrote:
>> On 5/11/11 4:51 PM, Robert Bonomi wrote:
>>> In article<E_ydndNE-PZOd1TQnZ2dnUVZ_oGdnZ2d@earthlink.com>,
>>> Reed<reedh@rmi.net> wrote:
>>>> The term "bit" still describes the speed of the raw "data transmission
>>>> over private lines".
>>>
>>> Sometimes "yes", sometimes "no".
>>>
>>> Consider analog line signalling where one 'symbol' represents multiple
>>> 'bits' in the original data stream.
>>>
>>> Thus the 'classical' distinction between 'bits' and 'baud' in more
>>> commplex
>>> analog data links.
>>>
>>> For an extreme case, consider the Telebit Corp "PEP" protocol, used in
>>> their 'trailblazer' (and compatible) modems.
>>>
>>
>> Well, yes, various methods have been used to increase the usable bit
>> rate of an otherwise band-limited channel. QAM, Trellis coding, etc.
>> However I think the the usable "speed" of the channel would still be
>> expressed in bits per second.
>>
>> Also I took "L or J's" comment as aimed at bytes, etc. Perhaps they
>> meant baud, since that always has been a common point of
>> mis-understanding when speaking of modem speeds.
>>
>> Thanks for the reminder, Reed
>>
>>
>
>Actually, I believe that Lisa and/or Jeff were pointing out that 1957
>was a very early use of the term "bit."
I suppose so, IF you forget about Nyquist in the 1920s, Shannon in the
1940s, and everybody else in between.
Date: Fri, 13 May 2011 10:41:11 -0700 (PDT)
From: Lisa or Jeff <hancock4@bbs.cpcn.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Battery technology
Message-ID: <8ec7bc9d-efc6-46f5-b771-fe5500aa9be8@w10g2000yqa.googlegroups.com>
A while back there was a discussion on this newsgroup about storage
battery characteristics.
The Sept 1970 issue of BSTJ has several detailed technical articles on
new lead-acid battery technology developments the Bell System
undertook to improve performance and economy. That might answer some
of the questions posed here.
http://www.alcatel-lucent.com/bstj/vol49-1970/bstj-vol49-issue07.html
For radio buffs, this issue includes an article about rain
interference: "Some Calculations on Coupling Between Satellite
Communications and Terrestrial Radio-Relay Systems Due to Scattering
by Rain".
Date: Fri, 13 May 2011 10:54:20 -0700 (PDT)
From: Lisa or Jeff <hancock4@bbs.cpcn.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: BSTJ Telstar
Message-ID: <c6f9424c-924d-4039-b6a4-387b04844038@v8g2000yqb.googlegroups.com>
On May 12, 12:39 pm, Lisa or Jeff <lisa_or_j...@invalid.telecom-
digest.org> wrote:
> Knowing of your interest in radio, you might find the following
> interesting. It's amazing the basic issues that we take for granted
> today all had to be carefully worked out.
Going back earlier, two articles on overseas shortwave radio:
http://www.alcatel-lucent.com/bstj/vol09-1930/articles/bstj9-2-258.pdf
http://www.alcatel-lucent.com/bstj/vol09-1930/articles/bstj9-2-270.pdf
Ship to shore radiotelephone:
http://www.alcatel-lucent.com/bstj/vol09-1930/articles/bstj9-3-407.pdf
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