| Re: Modems - Hayes - Instant Communications |
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 Wesrock@aol.comMon, 16 Jan 2006 16:38:06 EST
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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 such control. 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 communication. 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 automated.)
Wes Leatherock
[TELECOM Digest Editor's Note: Actually, J.C. Penny isn't the only one |
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