Control apparatus for an automated telephone attendant

Abstract

Automated telephone attendant equipment involving a technique for connecting an incoming call on an external line to one out of a plurality of telephone devices. Each telephone device is connected in an internal line branching off from the external line. A main control box is placed in an internal line. After it senses a ring on the external line, it processes an incoming identification signal, such as is characteristic of a facsimile transmission, for example, which contains information as to which particular telephone device is to be accessed. The main control box then generates a ringback signal which not only notifies the caller that the extension desired is ringing, as is conventional, but also contains a coded signal unique to the telephone device of interest. A local control box is provided in each internal line to normally block signals from passing to the telephone device from the external line. This local control box detects the coded ringback signal from the main control box and compares it with the code preassigned to itself. If a match is found, the local control box connects its corresponding telephone device to the external line.