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From: CAPEK%YKTVMT.BITNET@cunyvm.cuny.edu (Peter G. Capek)
Newsgroups: comp.dcom.telecom
Subject: Re: 50th Anniversary of Data Communications!
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Date: 16 Sep 90 20:01:35 GMT
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X-Telecom-Digest: Volume 10, Issue 651, Message 3 of 9


In recent postings, Will Martin and Dave Levenson have commented on the
first use of telephone lines to transmit data.  If what is really
meant here is tranmission of digital data over voice phone lines, I
believe the "first" may be around 1953 or '54; I've been unable to
determine the exact date.  The SAGE project, a joint effort of IBM,
Lincoln Labs (an adjunct of MIT which was established for the purpose)
and the Air Force claims a number of "firsts", among them this one.  I
quote from "History of the Design of the SAGE Computer - the AN/FSQ - 7" 
by Mort Astrahan, IBM Research Report RJ 3117, 1981:

   "Highlights of ...these innovations:

    Data communication over standard phone lines: The transmission of
    digital data over voice-grade lines at 1300 bits per second was
    pioneered by the Lincoln [Labs] people.  Jack Harrington's group
    of Division 2 designed the first modems to convert digital data to
    and from analogue waveforms that could be accommodated by
    voice-band channels.  The channels required special conditioning
    to minimize noise pickup and eliminate unequal phase shifts across
    the frequency spectrum.  The phase shifts were not noticeable in
    voice transmission but distorted the data waveforms."

By the way, Astrahan claims other "firsts" for SAGE: Light Pens (which
he calls Light Guns; this was a military system, after all :-) ),
time-sharing (which might better be thought of as multiprogramming),
I/O in parallel with computing, associative memory implemented using
drums, hot-standby duplexing, core memory in a production machine,
computer control of voltage margins, and components automatically
mounted on and soldered into circuit boards.


Peter Capek