Improvements in or relating to telephone systems

Abstract

Abstract 1,020,404. Automatic exchange systems. SIEMENS & HALSKE A.G. June 3, 1964 [June 7, 1963], No. 22874/64. Heading H4K. In an exchange having first subscribers provided with D.C. impulse transmitters and second subscribers provided with key-senders for code dialling, a transmission bridge which may be taken into use by either type of subscriber comprises an impulsing relay which brings up a delayed action dialling relay during reception of D.C. impulses and brings up an alternative relay which controls a code receiver during reception of code dialling signals. A calling line is connected through finder K to a transmission bridge Ue whereupon relays S and C come-up. Assuming that the caller is of the first type then during the first impulse of each train relay S falls back and brings-up slow-tooperate relay V (relay CA is momentarily energized but falls back when V operates since rectifier Gl1 is then reverse biased). Relays V and C hold for the duration of each train, while S repeats the impulses to a register WU. Similarly if a subscriber of the second type is calling then he also breaks the line loop during signalling so as to release S and bring up CA but in this case the accompanying code signal (two successive signals on one or both line wires) is received in a code receiver WE whereby the corresponding relays A to D comes up followed by CB. The latter, prevents V from operating, holds C and causes CA to remain up. The code signals are translated and may be stored in the register Wu.

Inventors

No inventors recorded.

Bibliographic Details