Abstract: An Internet protocol network alternate routing system comprises: a traffic control unit for detecting the state of congestion of an LAN, which is an Internet protocol network; a call control unit for establishing a link between an extension telephone and the LAN based on the detection results of the traffic control unit; a central processing unit for designating the signal path of voice signals that are transmitted from the extension telephone based on the results of establishing a link in the call control unit; and a switch control unit for switching the signal path that connects a path to the extension telephone. In a case in which the call control unit does not establish a link, voice signals that are transmitted from the extension telephone are rerouted by switching performed by the switch control unit to a leased line network by way of a leased line trunk.

Abstract: A virtual private line connection method allowing efficient and economical virtual private line service in the public ISDN is disclosed. When a SS7 (common channel signalling system No. 7) message is generated in response to a call originated by a terminal accommodated in a PBX, the SS7 message is encapsulated in an ISDN message and the ISDN message is sent to the destination PBX on a D channel. When the destination PBX receives the ISDN message, the SS7 message is read from the received ISDN message to establish the virtual private line between the PBXs.

Abstract: Disclosed is a system and method which can efficiently distribute local data supplied from a single maintenance terminal to all of nodes and can certainly make data synchronized among the nodes. One of a plurality of nodes constructing a PBX network is set to a master node 2 and the other nodes are set to slave nodes 3 and 4. Local data supplied from a data input unit 1 to the master node is retained in a data retaining unit 24 in the master node and is also formed in a transfer format obtained by adding a checksum of the local data and a destination node designated to each slave node to the local data by data editing means 22 in the master node. The local data in the transfer format is transferred by data transfer means 23 to the slave node through a transmission line 5 which can perform broadcast transfer.

Abstract: A verification code from a telephone terminal which requests a call forwarding service is registered into a switching system. When a call forwarding service establishing number is dialed from an arbitrary telephone terminal, the arbitrary telephone terminal is prompted to dial the registered verification code and a telephone number thereof. The switching system checks the dialed verification code against the registered verification code. If they coincide with each other, the switching system prompts the arbitrary telephone terminal to dial a call forwarding service establishing special number, the telephone number of the telephone terminal registered in the service and a forwarding destination telephone number, and then establishes a call forwarding service setup for the telephone terminal registered in the service.