Abstract: A plurality of routing modules in a switching network of a telecommunication system each includes several interfaces connected to a first channel concentrator via respective data stores receiving and temporarily memorizing incoming data words coding the voltage levels of message samples from associated peripheral units served by the respective interface. In response to commands from a control unit, included in the module, this first concentrator selectively transmits memorized data words in respective phases of a PCM frame to all the modules in the network. Outgoing data words issuing from any routing module are registered in other data stores and selectively extracted therefrom by a second channel concentrator under instructions from the control unit, the extracted data words being distributed by a channel expander commanded by the control unit to registers assigned to respective peripheral units.

Abstract: A telecommunication system, e.g. a telephone switching exchange, comprises a multiplicity of substantially identical modular units each including a microprocessor controlling the emission of departing digital messages by a transmitting section and handling arriving digital messages reaching a receiving section. Each modular unit is connected to all other units by an outgoing and an incoming two-wire line each including a signaling wire and a response wire. The signaling wire of the outgoing line of a given modular unit emits, in the presence of a departing message in a memory of the associated transmitting section, a data-ready signal to the receiving section of the modular unit for which that message is destined; the latter section, continuously scanning the signaling wires of all incoming lines, then halts its scan and sends back an acknowledgement signal on the response wire of the same line whereupon the message is sent out on the aforementioned signaling wire.

Abstract: Two intercommunicating functional units, namely a master unit such as a processor and an associated peripheral or slave unit, exchange 32-bit messages--with 24 information bits followed by 8 cyclic redundancy bits--by way of a control unit and upon initiation by the master unit. A receiving section of each functional unit includes a redundancy generator which, on the basis of the information bits of an incoming message, recalculates the redundancy bits in accordance with a predetermined polynomial code and sends the result to the control unit which has a similar redundancy generator responsive to the information bits of a transiting message for recalculating the same redundancy bits. The control unit compares the locally generated redundancy bits with those of the transiting message and those sent back from the message-receiving unit; in the event of a discrepancy, it identifies one or the other functional unit as the site of a detected error.

Abstract: Disclosed is a method and apparatus for digitally switching audio signals in a telephone communication system having a plurality of telephone stations with their voice communication channels selectively coupled by way of analog to digital and digital to analog converters through a switch matrix controlled from the output of a stored program controlled computer. The analog audio signals to be inputted to the digital switch matrix are converted to pulse width modulated digital signals, the digitized audio signals outputted from the matrix being reconverted to analog audio signals.