METHOD OF INTEGRATING ONE OR MORE ACCESSORY FUNCTION MODULES IN TELECOMMUNICATIONS SYSTEMS AND ACCESS CIRCUIT FOR USE THEREWITH

摘要

A method of integrating one or more accessory function modules in telecommunication systems is disclosed, especially digital telephone extension systems, where communication between two user terminals is achieved using time division multiplexing by assigning a pair of time slots through a central exchange, and by preassigning at least one particular time slot which can be accessed to allow communication between the accessory function module or modules and the user terminals. This allows said communication with the use of only a modest amount of additional circuitry and without placing an additional burden on the exchange system.