SUBSCRIBER'S PRIVATE COMMUNICATION SYSTEM

摘要

PURPOSE:To unnecessitate the centralized control using a PBX by providing a call control message monitoring means on each terminal equipment together with a means which fetches the control information on a transfer medium and sets and cancels the extension and outside line communication channels. CONSTITUTION:The control information which includes the information on the dead channels of a transfer medium shared by plural terminal equipments 3 is circulated on the transfer medium. Each equipment 3 monitors a call control message by a monitoring means 1 and then fetches the control information circulating on the transfer medium by a control means 2 after detecting a setting or canceling request for the extension or outside line connection. Then the extension/outside line signal channels are set/canceled based on the information on the dead channels included in the control information. Therefore it is possible to attain the extension communication among equipments 3 and the outside line communication secured with a public network via a terminal controller 4 without using any PBX in a subscriber's private network where a ring-shaped or bus-shaped transfer medium is shared by plural equipments 3.