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A Low-cost Fsk Modem Network for Polled Communication Systems.
MISSING :23 pages
A frequency-shift keying (fsk) modulator-demodulator (modem) network has been devised for the Bureau of Mines mine-monitoring systems. This network permits an unlimited number of remote stations to communicate with one central station over the same pair of wires. The network operates at a speed of 4,800 baud (bits per second) at distances up to 5 miles. This report describes the development and operation of the modems. The theory of operation, schematic diagrams, and printed circuit board layouts are provided. Although the modems were built for a specific application, a more general use is discussed whereby the network would operate with a typical serial channel format.
IH; Information Circular;
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division