|Re: Modems - Hayes - Instant Communications|
Mon, 16 Jan 2006 16:38:06 EST
All the discussion about rapid communication depending on modems on|
telephone circuits seems to miss the point.
The Civil War/War Between the States (1861-1865) provided the first
example of war more or less commanded from a central point and with
knowledge of what was happening in the field timely enough to exercise
We read repeatedly that Lincoln spent a good deal of time in the
adjacent War Department telegraph office to follow the war. (Some
think he got proficient enough to read the dispatches by sound, just
like the telegraph operators.) Whole armies could be and were moved
over large distances -- "redeployed" we would call it now -- based on
the exigencies of war.
This centralized control depended on the telegraph, a form of
communication not previously available in war. The telegraph is a
form of digital communication, a concept not previously in use.
Multiplexing of telegraph circuits, attained in various ways, was an
active field for R&D to reduce the cost of physical circuits.
Alexander Graham Bell was working at developing a frequency division
multiplex system when he first heard recognizable sounds -- twangs --
and made the leap to the idea that electric currents could be directly
modulated by sound by use of a suitable device (transmitter) and
demodulated by a suitable receiver.
For telegraphy, there was the disadvantage, of course, for commercial
use in the need for an operator at each end. Only such enterprises as
government, railroads, newspapers, news services and stockbrokers
generally could afford the labor costs.
The printing telegraph machine (Teletype and others) changed all that.
But that was an economic effect -- until into the 1950s, at least,
teletypewriters were no faster than skilled telegraph operators.
The transmission of images by modulating an electric current was in
practical use by the 1930s, with Wirephoto (Associated Press),
Telephoto (United Press) and Soundphoto (Inter- national News
Service). These were high quality halftone facsimile transmitters and
receivers, again requiring a technician at each end.
The first use I remember for the suction cups was in early business
facsimile machines, which laboriously used thermal imaging to write a
pretty poor line image only (no halftones) at the destination end.
Someone mentioned the demise of the Sears, Roebuck warehouse and
catalog center in Philadelphia as being due to the slowness of the
Certainly by 1950, and perhaps earlier, you could place an order in
person or by telephone at your local Sears store, it would be
transmitted immediately by telegraph to the Sears catalog warehouse,
and in many large cities available for pickup at the local store the
next day. A speed that has not been bettered yet, even though you
place your order on the Internet. It still will get there the next
day if you place your order with J.C. Penney, the only retailer still
offering this service.
The demise of the Sears and Wards catalog operations was due to their
inefficiencies in the warehousing housing, picking and shipping
systems of those two companies, not to the slowness of communication
with their customers.
(J.C. Penney's system was built essentially from scratch and the
warehousing, picking, packaging and shipping is pretty much all
[TELECOM Digest Editor's Note: Actually, J.C. Penny isn't the only one
|Post Followup Article||Use your browser's quoting feature to quote article into reply|
|Go to Next message: USTelecom dailyLead: "Cisco to Launch Consumer Electronics Products"|
|Go to Previous message: firstname.lastname@example.org: "Re: Public Wants Court to Okay Wiretaps"|
|TELECOM Digest: Home Page|