GB1336815A - Pcm telecommunications exchnage systems - Google Patents

Abstract

1336815 Automatic exchange equipment SIEMENS AG 17 Sept 1971 [30 Sept 1970] 43389/71 Heading H4K A compressing arrangement in a PCM, TDM exchange employs code converters to bring all the conference subscriber signals into the same 12-bit code before adding all the signals which are then converted back into the original 8-bit code in coder reconverters and transmitted to the subscribers. The Specification is only concerned with a compressing arrangement for at least four subscribers and if a subscriber is absent a zero word is inserted in his place. The four wire system shown has input stores SE1- SE4 of which one is allocated to each of the four conference subscribers to store the signal in the respective time slot arriving on highways EMLI-N. These signals are simultaneously passed through code converters NL1-4, registers R1-4 and the two stages of binary adders so that the total signals can now be passed through reconverters LN1-4 and stored in respective ones of output stores SA1-4. The stores are read out on to the transmitting highways SMLI-N in the subscriber's time slot. The highway switches are controlled by rotary address stores UI-UN which control the incoming highway switches through decoders DEI-N and the outgoing highway switches through delay VtV and decoders DSI-N. The switches controlling the reading in and out of the input and output stores are controlled from rotary address store U4 in a similar manner to the highway switches. In a modification single code converters and reconverters can be used and are connected sequentially to the input stores and registers and the adders and output stores respectively. It is also proposed that the stores can be connected in sequence to a single line from the incoming and outgoing highways.