First Modems (was RE: cctech digest, Vol 1 #379 - 30 msgs was Re: FYI: 25th)

From: Feldman, Robert <>
Date: Fri Feb 21 08:46:00 2003

(Did a little Googling yesterday)

Bob Scarborough
( says
In the 1930s, the acronym "modem" came into use, a contraction of
"modulator/demodulator". This was used in FDM multiplexing, to denote an
analog/analog function, where voiceband signals were modulated up into
"channel group" spectra of 12 to 110 KHz along with 11 others by using
carrier tones and selected sideband energy.

The timeline
at has
1955 Modem first described by Ken Krechmer, A. W. Morten, and H. E. Vaughn.

1958 AT&T introduces datasets (modems) for direct connection.


-----Original Message-----
From: Frank Arnold []
Sent: Friday, February 21, 2003 6:23 AM
Subject: Re: cctech digest, Vol 1 #379 - 30 msgs schrieb am 20.02.2003:
>Message: 13
>Date: Wed, 19 Feb 2003 12:50:39 -0800 (PST)
>Subject: Re: FYI: 25th Anniversary of Ward Christensen's BBS
>From: "Eric Smith" <>
>To: <>
>Stan Sieler asks:
>> but...does anyone know the first data of a binary (not ASCII)
>> file transmission via modem?
>I assume that was a typo, and you want the date, not the data?
>> (I know of some done in 1975, from an IBM
>> mainframe to a DG Nova.)
>At least as early as 1965 IBM sold equipment that could do this, so
>I rather imagine people probably did binary transfers even in those days,
>but I don't have any proof of it.


I found this: at photo 22 it claims:

22. Simplex.jpg. This console provided operation and maintenance of the Long
Range Inputs and Outputs. Simplex because there was no redundant hardware.
Each radar station fed digitized data to the DC over public telephone lines
first - they had to invent the modem!). The DC also sent data to the
neighboring DCs and to the Command Center (the AN-FSQ-8 computer).
Received on Fri Feb 21 2003 - 08:46:00 GMT

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