Communications switching system with modular switching communications

Abstract

A communications switching system is controlled as a peripheral device to a general purpose digital host computer or other host device. The switching system has a plurality of ports for telephone lines and/or trunks and makes connections to the ports. The host computer is programmable at high level to obtain customized switching applications. The switching processes are carried out in the switching system under control of high level commands. The commands are formatted to identify the command functions and the ports at which the switching and control actions are to be carried out. These ports may be provided by separate modular switching units, each having processors for carrying out the switching functions at the designated ports and for distributing the commands in accordance with the command format to the designated port regardless of which of the modular switching units has the port. Responses as to the execution of the switching events are also conveyed to the host computer in a format which designates the response function and the port at which the function occurred. The switching units may be equipped with asynchronous serial data links for connecting one or more host computers or devices to the modular switching peripheral units.