GB539033A - Improvements in or relating to remote control arrangements, such as for radio transmitters - Google Patents

Abstract

539,033. Radio transmitting systems. STANDARD TELEPHONES & CABLES, Ltd., and BOWSHER, E. A. H., Feb. 23, 1940, No. 3435. [Class 40 (v)] [Also in Group XXXVIII] A radio transmitter is controlled for alternative telephony and telegraphy over a line L1, 2 from a remote control unit provided with a microphone T, telegraph key MSK and keys for setting up the alternative sending conditions. Currents of opposite polarities are fed alternatively to the line through relays at the transmitter end, and the connection in the loop of either one of two rectifiers MRA, MRB determines which polarity shall be effective. A resistance R allows the intensity of current to be varied. Current is normally fed through relays ST, P, and closure of start key STK completes the loop through rectifier MRA and resistance R to energize relay ST only, whereupon relay TR completes the low tension circuit of the radio transmitter. Actuation of key HPK short-circuits resistance R and allows the operation of P, which switches on the high tension at low power for telephony and closes the carrier control circuit. Relay PS energizes and alters the connections of ST, P to the line. When key HPK is restored, reversed current through relays K, T is connected momentarily to the line during the release time of PS, and if key KK, which shares the same knob with HPK, is actuated at the same time, the loop is completed through rectifier MRB and resistance R. Relay T energizes and connects up TA, which switches on the high tension at full power for telegraphy, operates TS and holds PS. Telegraph key MSK by short-circuiting resistance R controls relay K, which in turn controls the carrier control circuit. In a similar manner, when key KK is restored, normal current through ST, P is connected to the line during the release time of TS to test whether key HPK is actuated.