LOW-SPEED SUBSCRIBER EXTENSION SYSTEM

摘要

PURPOSE: A low-speed subscriber extension system is provided to extend a capacity accepting low-speed subscribers, so as to increase use efficiency of a switch link in an ATM(Asynchronous Transfer Mode) switching system. CONSTITUTION: A low-speed subscriber board(70) is interfaced with a switch link through a system backboard(130), and receives cells transmitted from the switch link. And the low-speed subscriber board(70) multiplexes/demultiplexes the cells through UTOPIA(Universal Test and Operations Physical Interface for ATM(Asynchronous Transfer Mode)) interface(78), after switch link and ATM layer processing. A low-speed subscriber physical layer board(80) transmits physical layer-processed data to a low-speed subscriber, and turns the cells transmitted from the low-speed subscriber board(70) to clocks and data for serializing. A low-speed multiplexing/demultiplexing board(90) restores cocks and data in the serial data inputted from the low-speed subscriber physical layer board(80) through a cable, for conversion into word unit of parallel data, and transmits the parallel data to a corresponding low-speed extension board(110) through a low-speed bus(116). And the low-speed multiplexing/demultiplexing board(90) reads and multiplexes the cells inputted from an optional low-speed extension board, to transmit the multiplexed cells to the low-speed subscriber physical layer board(80) through a link processor(97). And low-speed extension boards(110) transceive cells with the low-speed multiplexing/demultiplexing board(90) through the low-speed bus(116), and transmit received cells of corresponding boards to a corresponding subscriber through a low-speed extension physical layer board(120) after physical layer processing.