ATM switching system

摘要

The invention refers to an ATM (Asynchronous Transfer Mode) switching system including a self-routing switch performing switching operation for cells carrying communication information, a cell phase synchronizing circuit incorporated in each of ATM line termination apparatuses serving as interfaces between transmission paths and said self-routing switch for matching on a plurality of lines accommodated in said ATM switch the temporal phases of the cells contained in information streams outputted from line termination circuits serving for establishing physical matching of electrical conditions, traffic rate and others between said transmission lines and intra-system lines, comprising. cell phase detecting means for detecting positions of cells in said information streams (information bit row) on said intra-system lines; a cell synchronizing buffer connected to an incoming line by way of an isolating circuit and to an outgoing line by way of a selector circuit and including a plurality of buffer memories each having a capacity corresponding to at least one cell; a write control circuit for extracting a cell from the input information stream, selecting sequentially one of said plurality of buffer memories constituting said synchronizing buffer and writing the cells in said buffer one by one in the order of arrival; register means for indication the written states of said plurality of the buffer memories; and a read control circuit for controlling said selector circuit on the basis of the information in said register means to select the buffer memory to be next read out from the buffer memories storing the cells for thereby performing read control with a phase generated in synchronism with a system clock in common to all the line.