LOCAL LINE TERMINATION DEVICE ON ODN OF ATM

摘要

PURPOSE: A local line termination device on an ODN(Optical Distribution Network) of ATM is provided to offer an integrated services digital network(IDSN) service as a basic service using an optical cable of one stripe per subscriber and offer video and distribution services. CONSTITUTION: A downstream frame processing part(1) receives ATM cells of a byte or word unit from an external ATM layer processor through a universal test and operations physical interface for ATM(UTOPIA), codes the received ATM cells, and performs a downstream frame insertion function, a bit interleaved parity-8 calculating and inserting function, a scrambling function, a header error control calculating and inserting function, and a parallel-to-serial conversion function. An optical transmitter(2) performs an electric-to-optical conversion operation with regard to serial frame data to output the converted value as a 155.520Mbps or 622.620Mbps optical signal. A controller(3) generates control signals required by downstream and upstream frame processing parts(1,7). A timing generator(4) receives a system clock to generate timing signals needed by each block. A microprocessor(5) performs a media access control protocol. A burst-mode optical receiver(6) restores received data by performing an optical-to-electric conversion operation with regard to an upstream 155Mbps optical signal and extracting a clock signal. A wavelength division multiplexing unit(8) multiplexes a downstream optical signal having 1550mm wavelength and an upstream optical signal having 1310mm wavelength so that the downstream optical signal is transferred to an optical distributor network and the upstream optical signal is transferred to the burst-mode optical receiver(6).