SYSTEM FOR SEARCHING IDLE SWITCHING TIME SLOTS DEFINING A SELECTED FOUR-WIRE COMMUNICATION CONNECTION THROUGH A SWITCHING NETWORK WORKING ON THE BASIS OF TIME AND SPACE-DIVISION

摘要

System for searching idle switching time slots defining a selected four-wire communication connection through a switching network working on the basis of time and space-division. A control arrangement for controlling and coordinating the required switching operations in a switching network is designed among others to search idle switching time slots which can be used for a requested four-wire communication connection. Thereto a recording memory is used for continuously recording for each time switch the idle-busy condition of switching time slots. During the search for idle switching time slots for a four-wire communication connection which has to be established via separate time switches at the input of the network, at least one pair of idle locations in the recording file which can be suitable for a fourwire communication connection that has to be established via one and the same time switch is skipped and reserved before a pair of idle locations in this recording file representative of the searched switching time slots for the requested connection that has to be established via separate time switches, is seized. This creates the possibility of making the chance of blocking for connections that have to be established via separate input time switches (external group connection) virtually equal to the chance of blocking for connections that have to be established via one and the same input time switch of the network (internal group connections).