Small PBX with parallel call facility - identifies incoming calls either at switching unit or at extension and uses microprocessor to handle calls

摘要

The system has an exchange line, a switching console, several extensions able to dial an exchange and a device to transfer and evaluate codes. The selection of a particular code by the central computer (-microprocessor) for recognising a state of parallel calling is evaluated in a memory in relation to the address of the extension selecting the code. For every incoming exchange call, whenever the call connection device is operated, the switching devices that connect the exchange line to the switching unit, and that connect the exchange line to the extension, concerned, are operated. The code numbers of the calling station and of the selected called station are transferred at each step.