Italtel Societa Italiana

Cselt-centro Studi E Laboratori

Italtel Societa Italiana Telecomunicazioni

Luigi Canato

Amilcare Bovo

Piero Belforte

Bruno Bostica

Luciano Pilati

Convertible switched telephone exchange

A switching unit for the selective transfer of bytes concurrently arriving in successive time slots over eight incoming signal paths to as many outgoing signal paths with intervening temporal and/or spatial transposition comprises a byte memory, loaded by way of a series/parallel converter and read out by way of a parallel/series converter, under the control of a routing memory dialoguing via a logic network with a microprocessor. The latter, through instructions sent to the logic network, may command the blocking of the readout from the byte memory onto an outgoing path during a given time slot, the insertion of a particular byte into such a time slot, or the transfer of selected bytes from either memory to the microprocessor itself. In particular, bytes from the first time slots of PCM frames arriving over selected signal paths can be so extracted from diagnostic purposes.

Switching unit for the transfer of digitized signals in PCM system

A network for selectively switching channels from n incoming PCM links to as many outgoing PCM links comprises two sections of a receiving-side stage with n input terminals each, connected in parallel to respective incoming links, and with m output terminals working into an intermediate stage with 2m input terminals and as many output terminals. The latter are connected to respective input terminals of two sections of a transmitting-side stage with n output terminals each; homologous output terminals of the two transmitting-side sections are alternatively connectable to respective channels of n outgoing PCM links by means of multiplexers which are switched by a logic unit under the control of a processor also detecting possible malfunctions in any section. Each stage consists of a multiplicity of temporal or spatial switching matrices. With m lying between n/2 and n, and with all matrices operating normally, the logic unit routes about half the incoming channels through each receiving-side section and each transmitting-side section; the matrices of the intermediate stage provide a plurality of alternate paths between any receiving-side matrix and any transmitting-side matrix. When a receiving-side or transmitting side matrix fails, the routes established therethrough are transferred to its counterpart in the other section of the respective stage; failure of an intermediate matrix results in a redistribution of its routes through the remaining matrices of this stage.

PCM Switching network with surplus capacity

Growing community of inventors

Milan, Italy

Luigi Canato