Digital timeslot and signaling bus in a digital pbx switch

Abstract From the Canadian patent

A switch in a digital PBX system supporting both centralized and distributed switching techniques. The switch has nearly universal and parallel bus between line card modules. Then a timeslot bus capable of having more than one module may communicate voice PCM or data signals during one timeslot. The bus also has a signaling bus by which line card modules are selected to communicate with a central control module by a single line to maintain the universality of the bus. Signaling information is also passed between a selected line card module and the central control module by a pair of parallel lines.