EXCHANGE SYSTEM

PROBLEM TO BE SOLVED: To catch VPI and VCI for PVC with a single request for setting of PVC even if the catch of SVC communication and that of VPI and VPI compete with each other. SOLUTION: An SVC controller 11 requests the catch of a channel to be used in a channel controller 13 each time when initiating communication. A PVC controller 12 requests the channel controller 13 to catch a channel to be used when initiating communication. The channel controller 13 controls the vacancy/engagement of all virtual channels to be used, and in case that there is a channel catch request from either the SVC controller 11 or the PVC controller 12, it searches a vacant channel using a channel vacancy/occupation table 14, and in case that a vacant channel is found, this outputs it to the controller at the request source. COPYRIGHT: (C)2003,JPO