Patent ID: 7843971
Filing Date: 2010-11-30
Classification: H04M,H04Q

Abstract:
1. A modular expandable telecommunication system, including a private automatic branch exchange system (PABX), comprising a main or primary cabinet and at least one expansion or secondary cabinet, which are interconnected with each other in order to obtain an extended telecommunication system with increased connection possibilities for extensions and trunks, wherein the main cabinet and each of the expansion cabinets comprise a transmission interface unit allowing connection of said at least one expansion cabinet with said main cabinet via a single transmission link conveying voice/data channels and low level or local signaling for performing at least mutual synchronization and clock recovery for all interconnected cabinets, the main cabinet comprising a master clock device, a central processing unit (CPU) for running an application and a digital signal processor (DSP) for routing higher level messages issued by the CPU depending on the physical location of a destination cabinets wherein each transmission interface unit comprises means providing synchronization with clock recovery and frame adjustment, a control channel of the corresponding expansion cabinet, remote resetting and downloading of software resident on said expansion cabinet, connecting means for short or long haul transmission and line coding and/or scrambling.