Zellenvermittlungseinrichtung

摘要

A cell exchanging apparatus which distributes cells input through a plurality of input lines to output lines by destination for output. Without stopping the operation of the cell exchanging apparatus, active and standby cell switches of the cell exchanging apparatus can be changed over. The cell exchanging apparatus comprises a first and second cell switches, input selectors for feeding input cells only to either of the first and second cell switches, and output selectors for outputting cells output from either of the first and second cell switches to an external system. When a change-over is instructed by a system change-over signal, the input selectors start to feed input cells into the cell switch in the standby mode. When detecting completion of cell output operation from the active cell switch, the output selectors select a new active cell switch. Upon detection of completion of cell output operation from the former active cell switch, a controller sends an output permission signal to the new active cell switch. Resultantly, the new active cell switch starts to output cells to the output selectors which then output the cells to an external system.