EXPANSION SUBSYSTEM FOR USE IN A COMMUNICATION SYSTEM

In a communication system, a modular expansion subsystem comprised of a plurality of general purpose slots disposed in the system cabinet, for receiving one or more co-operatively shaped interface modules connected to associated peripheral units, such as RS232C computer ports, answering machine interface circuits, local area network interface circuits, modems, etc. Additional slots are disposed in the cabinet for receiving one or more co-operatively shaped line or trunk interface modules connected to associated subscriber sets and outside telephone lines. A further slot is disposed in the cabinet for receiving a co-operatively shaped memory module in which an operating system program is stored. The various modules communicate with a central microprocessor of the communication system, which executes the stored operating system program, for identifying the various types of modules and the particular slots in which they are disposed. The modules can be easily installed by the user, without requiring the services of a trained technician, and the subsystem is entirely modular such that expansion is accommodated on a "pay as you go" basis.