Patent GB-1164716-A (GB)
Title: Improvements in or relating to Telecommunications Exchange Systems
IPC: H04Q3/00
Filed: 1967-10-02
Abstract: 1,164,716. Automatic exchange systems. SIEMENS A.G. 2 Oct., 1967 [30 Sept., 1966], No. 44663/67. Heading H4K. A satellite exchange identifies a calling subscriber and relays the identity to the main exchange from which a first signal is reverted to effect disconnection of the calling subscriber from the identifying circuit, a second signal being reverted to connect the calling subscriber to a main exchange line. As shown the identifier comprises an m x n diode matrix with co-ordinate relays Xl-Xm and Yl-Yn, the X and Y relay operating to a calling subscriber Tln and indicating his identity direct to a control circuit KS. Relays L1-L4 enable a data link sk from the control circuit KS to be connected to any of the exchange lines HL1-HL4 and the control circuit uses this path to send the calling subscriber's identity to the main exchange where it is stored pending release. The main exchange replies by directing the control circuit KS to energize its terminal Tan to gate the Y relay identification mark from contacts lyl-lyn to the latching relay matrix T, a row wire of which is primed directly by the X relay identification mark from the contact set 1x1- 1xm. The consequently latched one of the relays T11-Tmn of the matrix T disconnects the calling subscriber's line from the identification matrix. Latching relay matrices K1-K4 are employed to connect the respective main exchange lines HL1-HL4 to the satellite subscribers' lines. Depending on which exchange line is employed for the call a signal is sent from the main exchange directing the control circuit KS to pulse the appropriate one of terminals K1an-K4an whereby the X and Y identification relay marks are operative to latch up the relay K corresponding to the calling subscriber in the matrix associated with the exchange line seized for the call. To release the connection the main exchange delivers the calling subscriber's identity to KS to operate the corresponding X and Y relays and instructs KS to pulse its terminals Tan and K1/4ab whereby the latching matrices T and K1-K4 are reversely energized to unlatch the calling subscriber's relays T and K. Incoming calls are established by sending the wanted subscriber's identity to KS which brings up the corresponding X and Y relays, pulses terminal Tan to operate the wanted subscriber's T matrix relay to disconnect his line from the identifier, and pulses a terminal K1an-K4an to operate the wanted subscriber's K matrix relay to connect his line to the seized exchange line. Connections between satellite subscribers are made by connecting both subscribers to the same main exchange line which supplies battery from the main exchange. Permanent loop condition of a satellite subscriber's line may be dealt with by directing KS to operate the associated relay in the T matrix. As this withdraws the service of the identifier the loop ceases to be a disturbance. Contact operation of the K matrices may be tested from the main exchange by seizing two main exchange lines and operating a satellite subscriber's K relay in each of the associated K matrices. If the K relay contacts operate the exchange lines should be looped by the satellite subscriber's line. The identification matrix can be tested from the main exchange by connecting a particular satellite subscriber's line to a main exchange line without disconnecting the identifier. A calling condition from the satellite subscriber can in this way be simulated from the main exchange which receives the identity of the line from KS for comparison with the identity of the particular line as originally postulated.