Patent GB-909883-A (GB)
IPC: H04L12/54
Abstract: 909,883. Telegraph-exchange systems. STANDARD TELEPHONES & CABLES Ltd. Feb. 2, 1959 [Feb. 6, 1958], No. 3992/58. Class 40 (3). A message storage distribution system, particularly for telegraph-exchange systems, comprises a number of interconnected switching centres, each serving a number of stations and having means for passing into the system messages which have a plurality of routing indicators, each of which represents a station to which the relevant message is to be sent. The system includes registers at the centres in which details of the message retransmission to its destination are booked. When messages received at one centre have been retransmitted from another centre, the only routing indicators which cause a booking to be made in both centres are those whose prescribed routes involve both the centres concerned. Messages retransmitted contain only the indicators of stations which can be reached over the outgoing lines concerned in the retransmission. Redundant indicators are deleted from incoming messages before retransmission and the gaps closed up so as to present an uninterrupted formation retransmission. Signals received at 21 are recorded in a track of a magnetic drum 22 and subsequently passed at high speed to a magnetic recorder 11 comprising an elongated tape or loop capable of carrying a number of completed messages from its associated line. The several recorders 11, each individual to an incoming line, are connected to a distributer 12a. This distributer feeds via a decoder 12 to a second distributer 12b. Decoder 12 examines the routing indicators at the head of each message and sets 12b accordingly. Distributer 12b can be set to several different directions simultaneously for broadcasting. Each outgoing line has associated with it apparatus shown to the right of 12b. Control circuit 13 feeds store A or store B, stores having very large capacity, and is also connected to booking register circuits 14, each provided with individual tracks 17 on a magnetic drum. The booking information comprises the priority of the message, its chronological order, and the identity of the store A or B to which the message is being sent. Each booking track 17 has a section individual to each outgoing line, and sub-sections corresponding to the priority categories of the messages, the sub-sections being variable in size and position according to the occurrences of the various priorities. While decoding is proceeding the message is stored in the decoder and when all the routing indicators have been decoded and the routes set up only the indicators not already used are passed to the selected booking registers, followed by the message which is fed to store A or B of the selected line. The booking registers cause the booking information to be put in the next available position in the required subsection. Additional bookings are interposed between existing bookings, the booking information in the next lower category being displaced. The provision of two stores A and B, with each outgoing line ensures that a store is always available to receive signals from an incoming line, even when retransmission to the outgoing line is in progress. The stores A, B comprise multi-track tapes and the track upon which each particular message is recorded is stored in the booking register. Messages retransmitted are not deleted from the stores, but an indication is given of a message which has been retransmitted so that it can be distinguished from others not yet retransmitted. signals extracted from store A or B pass to a drum store 23 which passes the signals at high speed to unit 24 which reduces the signal speed to that of normal telegraph signals prior to transmission on the outgoing line. If the amount of traffic for a particular direction is large, several outgoing lines may be used in parallel for this one direction. In such a case only one pair of stores A, B is provided, the outputs from these feeding a distributer which feeds a tape store individual to each line, Fig. 8 (not shown). Specifications 685,932, 790,914, 791,216 and 907,100 are referred to.