Patent GB-1260769-A (GB)
Title: Improvements in or relating to automatic telecommunications exchange systems
IPC: H04Q3/545
Filed: 1969-12-01
Abstract: 1,260,769. Automatic exchange systems. SIEMENS A.G. 1 Dec., 1969 [2 Dec., 1968], No. 58559/69. Heading H4K. Connection data, such as wanted destination codes originating from connecting relay sets R11, R1n, R2x, R2y, is registered in one of a group of intermediate stores P1, P2 and causes a demand for the services of one of a group of control units S1, S2, the seized one of the control units staying connected to the intermediate store for the duration of the connection establishing process and supervising the transfer of data between itself, a translator from the group 1U, 2U, and a marker from a group of markers. The exchange has switch sections TKF1, TKF2, and TKF3 providing connections from incoming relay sets R11, R1n and R2x and R2y, to outgoing relay sets Ue. Each switch section is served by a pair of markers such as M11, M12 for section TKF1. Each marker may control the switch section in respect of a particular phase in the setting up of a connection. A switch section can, therefore, be subject to the concurrent control of markers serving different connections. If one marker fails its companion exercises both phases of control. Two circuits 1U and 2U are employed alternately to provide network terminal identities and class-of-service data in respect of connections being set up by a control unit. Transmission of data between control units, markers, and circuits 1U or 2U is made by way of duplicate data buses Da, Db. One bus can take control unit/marker traffic while the other takes control unit/circuit 1U or 2U traffic, the function of the buses being interchanged from time-to-time. If one bus fails, the other takes all traffic. The control units obtain exclusive use of a bus by signalling the wanted marker or circuit 1U or 2U, over individual wires of a demand bus sum, causing the return over a bus of the address of the wanted equipment as compiled by a demand scanner Za or Zb which continually scan the equipment for demand conditions and effect a one-at-a-time usage of the buses. Recognition of the wanted equipment identity by the control unit causes the transmission of data to the wanted equipment as connected by a scanner over a bus. If such a connection over a bus is not released within a given time a fault is presumed and indicated. Data transmission over a bus may be initiated by a marker, or one of the circuits 1U, 2U, in the same manner as it is initiated by a control unit. If a marker establishes a connection over the exchange network it informs the control unit engaged for the connection and the control unit updates the associated intermediate store. If the marker fails to find a connection it calls in the control unit for a further attempt. If the marker finds no connection is possible the intermediate store is updated accordingly by way of the control unit. While a control unit is waiting for service over a data bus it checks its data for self-consistency and traces errors for their origin in faults. Data received by an intermediate store from a control unit is acknowledged. The intermediate stores are grouped for access to corresponding control units but each control unit may be arranged to be accessible to any intermediate store. The intermediate stores are accessible to exchange relay sets over switches AK1, AK2. Test connections may be set up in the system by using an auxiliary intermediate store Pv, or by use of an auxiliary control unit V.