A transistorized multiplex telegraph set

INCREASED USAGE of radio teletypewriter communication has widened the demand for facilities for multiplexing teletypwriter channels on a single radio circuit, for economy of frequency spectrum and equipment. Many of the potential applications of multiplex require smaller and lighter equipment than heretofore available, with unusually high reliability. The developmental transistorized 4-channel time division multiplex equipment designed to meet this potential demand is functionally similar to, and compatible with, the AN/FGC-5 electronic multiplex, which has been in general use since 1950 on long-haul high-frequency radio circuits. In all active electronic functions such as switching and amplification, as well as in the power supply, only solid-state devices are employed. There are no vacuum tubes in the set. This equipment is designed to be an integral part of a time division multiplex system wherein two, three, or four start-stop telegraph channels are combined for transmission over a common communication circuit.