Patent GB-509146-A (GB)
Title: Improvements in or relating to electrical remote control systems
IPC: H04Q9/14
Filed: 1937-12-10
Abstract: 509,146. Electric control and signalling systems. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., CLOUGH, N. H., and OLIVER, E. C. Dec. 10, 1937, Nos. 34309 and 34310. [Class 40 (i)] In a remote control or indicating system, more particularly for controlling or supervising the control of a radio transmitter, a plurality of selections may be effected by positive and negative impulses transmitted over a two-wire line circuit under the control of synchronouslyoperated relay chains located at the control and controlled stations. The impulsing arrangements are such that an impulse cannot be transmitted until the preceding impulse is registered at the controlled station. Figs. 1 and 2 (34309/37) show the control and controlled stations respectively, the system being adapted to select in accordance with the positions of the switches 1SW, 2SW, 3SW, the nature of the'transmission, viz., ICW, CW or telephony, the wavelength and thepower of a radio transmitter. Synchronously-operated relay chains BA, MF, A ... L of the two-step type are provided at the two stations respectively, the chains being operated to switch sequentially the two-wire line TL into association with the contacts of the switches 1SW, 2SW, 3SW and the pairs of relays A, B; C, D; &c. The polarity of the impulses is determined by the setting of the switches and one or other relay in each pair is operated in accordance with the polarity of the impulse. The pairs of relays effect selections of the groups of outlets TR1 ... TR4, WL1 ... WL4, TP1 ... TP4 which correspond to the nature of the transmission, the wavelength and the power of the radio transmitter. The sequential operation of the system is started by closing the switch. FO and thereby energizing the line relays L, X. Relay X pulls up Y, A or B and the latter opens the line circuit to terminate the first pulse and effect the transference of the line to the lower contacts of 1SW and the pair of relays C, O through the intermediary of relays BA, AB. The line circuit is again closed and a second positive or negative pulse is transmitted to operate one or other relay C or D which opens the line and thereby transfers the line to upper contacts of 2SW and relays E, F. The sequential operation is continued and is such that an impulse cannot be transmitted from the control station until the preceding pulse is registered in the controlled station and the line circuit is opened by the operated relay. At the termination of selection, a further pulse is sent to operate relay SC and an indicating lamp SCL and a final pulse, the polarity of which is determined by the position of 4SW, pulls up a relay PO to switch operating power on to the radio transmitter. A supervisory relay TR for the radio transmitter controls relay PO and co-operates with relay X to pulse the line and flash a lamp LT in the event of failure of the transmitter. Rectifiers 1RT, 2RT are used to determine the polarity of the incoming pulses ; alternatively, polarized relays may be employed. The switches 1SW, 2SW, 3SW may be of the 4-position barrel type and may be interlocked with the switch FO. In a modification (Fig. 1 (Comp., not shown), the relay X is replaced by two relays connected to the line through rectifiers and opening of the line circuit at the controlled station to terminate a pulse is controlled by a relay which is responsive to the operation of the selected control relays of the radio transmitter. In another arrangement, the two-winding relays A ... L are replaced by single winding relays which are supplied from a local source of power. In a further modification, the selective equipment at the controlled station operates an indicator board for giving instructions to an engineer who manually operates the control circuits of the radio transmitter.