SYSTEM AND METHOD OF THROUGH SIGNALLING IN A DIGITAL COMMUNITY OFFICE TELEPHONE EXCHANGE

摘要

A discrete through signalling network and method for use with a digital central or community office (DCO) switching system wherein control and voice communications are isolated from one another and the uppermost element of the DCO common control hierarchy is a stored program processor. Supervisory status information or logic state information to be used by the receiving circuitry for either controlling supervisory states or as logic control information is communicated by the through signalling network. A preprocessor sequentially accessible to the ports of the telephone switching system determines whether the information relating to a given port is to be transmitted to another selected port, or is to be acted upon by selected control circuitry of the telephone switching system, and has a memory with an individual address and corresponding storage section for the information relating to each port. Combinatorial logic organization means are operable to sequentially update the information stored at the storage section for each port during that port's accessibility to the preprocessor.