Apparatus and Method for Inter Exchange Unit Relay Call Process of ISDN User Part in Telephone Exchange

摘要

An apparatus and a method for processing relay call between stations of an ISDN user part in a switch are provided to improve completion ratio and call communication for improving the relay occupying failure by error of management status between switching devices. An originating part(21) requests relay call connection corresponding to a call connection request from a subscriber. A routing controller(22) receives relay call connection situation and performs a call connection attempt control after transmitting a routing request message when requesting relay call connection from the originating part. IAM is transmitted by a first ASP according to a routing request message from a routing controller. An ASP part(25) retransmits the IAM from the routing control and attempts the transit call connection by a second ASP according to a routing request message.