GB370500A - Improvements in or relating to impulse transmitters for use in electrical signallingsystems - Google Patents

Abstract

370,500. Electric signalling systems. ASSOCIATED TELEPHONE & TELEGRAPH CO., 1033, West Van Buren Street, Chicago, U.S.A. Dec. 1, 1930, No. 34899/31. Convention date, Dec. 11, 1929. Divided on 368,369. Drawings to Specification. [Class 40 (i).] Relates to an electric signalling system, more particularly for signalling stock quotations to a plurality of receiving stations, wherein a stock, price and nature of price may be registered as digits in relay registers under the control of keyboards and each digit is transmitted in the form of a fixed number of positive and negative impulses, the strengths of which are varied in accordance with the value of the digit. The impulses operate relay registers at the receivers, the registers at each receiver controlling a local impulse sender which operates the indicators. The system described is identical with that described in Specification 368,369, but the invention resides in the manner in which the main and local impulse senders co-operate with their counting relay chains. The arrangement of each sender is such that impulses are transmitted to the external circuit at a given speed and to the corresponding counting chain at a sub-multiple of that speed. The first relay of a counting chain pulls up at the beginning of an impulse sent to the chain and a second relay is operated at the end of the impulse. In the main sender a pair of relays is operated in this manner for each group of four impulses sent to the external circuit while in the local sender at the receiver, two impulses are sent to the indicators for every impulse sent into the counting chain. The counting chain in the main sender is adapted to associate the stock and price digital registers successively with the impulse sender and that in the local sender is associated with the price registers at a receiver. Certain of the counting relays in the main transmitter are adapted to count a pause of predetermined duration at the end of the transmission of a complete quotation in order to delay signals corresponding to a subsequent quotation. Specification 370,499 also is referred to.