29 Years of the Digest ... founded August 21, 1981
The Telecom Digest for May 15, 2011
====== 29 years of TELECOM Digest -- Founded August 21, 1981 ======
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Date: Fri, 13 May 2011 07:20:01 -0500 From: firstname.lastname@example.org (Robert Bonomi) To: email@example.com. Subject: Re: History Early Data transmission technical considerations Message-ID: <0PednWQbcvFsvFDQnZ2dnUVZ_ridnZ2d@posted.nuvoxcommunications> In article <4DCC8263.firstname.lastname@example.org>, Jim Bennett <email@example.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<firstname.lastname@example.org> 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 <email@example.com> To: firstname.lastname@example.org. Subject: Battery technology Message-ID: <email@example.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 <firstname.lastname@example.org> To: email@example.com. Subject: Re: BSTJ Telstar Message-ID: <firstname.lastname@example.org> 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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