Abstract: In a telephone network including a PBX connected between a central/public office switch and one or more terminals where a computer telephony interface is connected to the PBX, a system operatively associated with the computer telephony interface and responsive to an operational characteristic of the PBX for sensing, detecting and identifying the type of PBX connected to the computer telephony interface. The operational characteristic utilized is the DC power levels for various PBXs. The system automatically senses, detects and identifies the type of PBX which is connected to the computer telephony interface. Automation of this procedure simplifies the user interface by providing the computer telephony interface with information which it can then use to configure itself and function in the required mode without having any type of user input.

Abstract: An improvement to a telephone system (10) having a first signal generator (21) which outputs a control signal only when it receives a certain request signal generated by the telephone system's client telephone (12). The invention contemplates a method and apparatus to generate a desired control signal when a request signal incapable of activating the first signal generator is produced by a client telephone (12).