CELL EXCHANGING APPARATUS

摘要

An ATM cell exchanging apparatus includes an ATM cell switch for a first system #1 and an ATM cell switch for a second system. These cell switches distribute input cells to appropriate output lines. The system also includes selectors for switching the ATM cell switches in accordance with a selection signal that is output from an external system. The ATM switches output an idle cell when there is no cell to be output. When the selector judges that it is necessary to switch the systems as indicated by the change-over signal, the selector switches the system after it confirms that an idle cell is output from both ATM cell switches. The idle cell that is output indicates that there is no cell stored in either system; thus, it is easy to switch the systems without causing the duplication or omission of a cell.