American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 420
Diplex. 351 This is one of several aiTangements, of which the first was devised by C. F. Yar-ley, to increase the capacity of a wire by superposing pulsatory current signals uponthe regular Morse signals. To accomplish this result successfully it is necessary, as in simultaneous telegraphyand… … VARLEY-ATHEARN SUPERPOSED CURRENT SYSTEM. The first requirement is met by the use of apparatus which sets up momentary cur-rents of comparatively feeble strength. These currents may consist of a single pulsa-tion for each character of a signal, as in the Edison phonoplex (next described), oreach…
Telegraph
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