Time slot interchanger and control processor apparatus for use in a

Abstract

A telephone switching network is disclosed, which network is adapted to provide connections between a plurality of input subscriber lines. The network includes a time slot interchanger which comprises a transmit switch memory and a receive switch memory. The transmit and receive memories are capable of storing data at addressable storage locations, which data is indicative of digital data to be transmitted from a line circuit and digital data to be received by a line circuit during a connection between the two line circuits. A connect memory is also employed for storing data indicative of connections to be made between line circuits. The connect memory as well as the switch memories are controlled in operation by a processor, which processor includes an access control means. The processor and the access control means are operative to cause the connect memory to couple corresponding storage locations of the transmit and receive memories indicative of one subscriber line to corresponding storage locations indicative of another subscriber line. In this manner, any line associated with the system can communicate with any other line. A trunk interface is provided to enable each subscriber associated with a first switching network as above described to communicate with other subscribers associated with an identical switching network via a communications link or trunk. Also disclosed is a unique data format to enable the use of an asynchronous trunk for communication between two or more switching systems of the above described configuration. The data format enables easy detection and recognition of null characters, control characters and data characters by utilizing a unique eight digit format for each of the above described characters.