ES373645A1 - Improvements in or relating to data-processing systems - Google Patents

Abstract

Processing of call connection data in a telephone exchange system involves control circuits S1 to Sm and circuits such as allotters U1, U2, transfer of data between a control unit and an allotter being effected in response to a demand from the allotter by way of a circuit individual demand wire in a cable uz, demands existing in the cable uz being detected by a scanner distributor Z1 which gives access to a data bus system US, SU for the data transfer. Once a bus is seized for a demand the identity of the calling unit and/or the wanted unit is sent over the bus to engage the service of the control unit. If such a data transfer is required at the instance of a control unit S1 to Sn, a demand is made direct to the wanted allotter over an individual wire of the cable Sm. The allotters contain scanners whereby the demand is detected along with the identity of the calling control unit and the allotter can seize the data bus as described above. Markers M1 to Mm similarly gain access to a bus system MS, SM over demand wires mz supervised by a distributer Z2, or in response to a demand over cable Su, to exchange data with a control unit. Demand wire cables mz1 and uz1 allow the bus systems US, SU, and MS, SM, to exchange roles from time-to-time so that the allotters and markers are alternately served by one and the other bus. If one bus system fails the other bus system can serve both allotters and markers. The bus systems have separate GO and RETURN loops connected from send to receive circuits in the distributers Z1 and Z2. Allotters and markers are coupled by transformers in shunt across each transmission pair while control units are coupled to transformer windings in each leg of each pair, Fig. 2, not shown. Processing of a particular connection involves a series of data transfers over the bus system each transaction being interleaved with similar transactions conducted on behalf of other connections.