Scanner for a centrally controlled telephone switching system

Claim 1

A switching system scanner of use in a switching system incorporating a plurality of units for supplying data to a central unit and a plurality of different circuits to be scanned, said circuits being distributed in groups of units, said scanner comprising a first recording device for receiving from the central unit the address of a first group of units to be interrogated, an adding unit for indexing the contents of the first recording device, a second recording device provided for receiving data indicating the results of interrogating a group of units, said second recording device placing the interrogation results at the central unit''s disposal, a sequential circuit operated under contRol of the central unit and delivering time control signals for controlling the different operations carried out by the scanner; during the scanning of unit groups, the central unit supplying the scanner with the address of the first group to be interrogated and starting the sequential circuit; the scanner including means under control of the sequential circuit for interrogating the unit group whose address is supplied writing the scanning result into the second recording device, and then blocking the sequential circuit operation; the central unit reading out the contents of the second recording device; the central unit then starting anew the sequential circuit which then controls the operation of the indexing device which indexes the group address stored in the first recording device in order to interrogate the groups designated by the new address thus obtained, the sequential circuit being then again in its initial position and controlling the next group interrogation, and so on until all the groups have been interrogated, said system thus relieving the central unit from the work of the calculation of the address of each group to be interrogated while leaving to it the processing of the obtained data in order to provide maximum flexibility to the system.