Nec Corporation

Kiyokazu Otsuka

Minako Takai

Hiroyuki Watanabe

Yoshio Itagaki

In an internal line control system, a telephone having an Internet protocol (IP) and capable of being connected to the Internet through the communication mode, includes a device for storing an IP address of a private branch exchange, and a device for sending a switching request to the IP address of the private branch exchange while specifying identification information. Concurrently, a private branch exchange having an Internet protocol (IP) and connected to the Internet through the communication mode, includes a device for storing a correlation between the IP address of the telephone and an internal line number depending upon the identification information, and a device for transmitting, depending upon the correlation between the IP address and the internal line number, a control signal and a speech communication signal for an internal line telephone of the internal line number to an address specified by the IP address. This allows a control to be switched over to the internal line telephone connected to the Internet so as to inherit various types of settings for the internal line telephone directly accommodated in the private branch exchange.

Internal line control system

The invention provides a private branch mobile communication apparatus and method which allows hand-over without interruption of communication and makes it possible to allow a service from a private branch exchange of a home node to be utilized as it is even if a radio terminal moves from the private branch exchange of the home node to another private branch exchange. A network common database, a local database and a memory section are stored in each of private branch exchanges. When a radio terminal forwards a position registration request to a radio base station belonging to a second private branch exchange other than the home node to the radio terminal, the second private branch exchange refers to the network common database to access the local database and the memory section of the private branch exchange of the home node, and then refers to the network common database to perform position registration into the private branch exchange of the home node and extract service data of an additional service to be performed by the private branch exchange which has received the position registration request other than the home node.

Private branch mobile communication system and method

The present invention provides a private branch exchange which allows the same system call sign (SYS-ID) to be shared with other private branch exchanges for allocating it to general cell stations. The private branch exchange (PBX), to which a control cell station (CS) is allocated, communicating with mobile stations (PS) reads the system call sign from the control cell station where the system call sign is stored in advance. The system call sign is stored into cell stations in a plurality of private branch exchanges connected to each other when the cell stations belong to the same group as that of the control cell station of the first mentioned private branch exchange.

Private branch exchange

In a PBX network, a global database is provided in each PBX node for storing shared data for verification of authorized mobile stations when accessing the network via a wireless cell-site station. During a wireless mode, a mobile station monitors the strength of its downlink signal from a first cell-site station of a first PBX node. If it falls below a threshold, the mobile station begins a scan across the spectrum. If a strong signal is detected, it stops the scan and transmits a handover request message to a second cell-site station transmitting that strong signal. The second node receives the message via the second cell-site station to establish the mobile's verification. If the mobile station is an authorized user, the second node transmits a handover grant message to the second cell-site station, transmits a command message to the first node for a switchover to a link between the first and second nodes, and connects the link to the second cell-site station.

Handover arrangement for mobile station moving across the boundary of wireless cell-site stations of adjacent PBXs

A private communications network system allows a mobile station to be used in a different private communications network than that in which it is registered, by a method of authenticating the mobile station outside of its home private communication network. When a mobile station 17 requests location registration in a private communications network 2 in which the mobile station 17 is not registered, a control unit 22 of a PBX 21 in the private communications network 2 requests a network common data management unit 3 to send group data which is used to identify a private communications network 1 in which the mobile station 17 is registered. Control trait 22 then requests a PBX 11 in a private communications network 1 to send subscriber data 33 of the mobile station 17. The mobile station 17 is authenticated in the private communications network 2 by the subscriber data 33 sent from its home private communications network 1, whereafter the mobile station 17 can make calls from or can receive incoming calls in the private communications network 2. Billing data for calls the mobile station has made in the private communications network 2 is transferred and stored in the home network common data management unit 3 on a group basis.

Private communications network system and method of authentication for a

In a communication system for a plurality of terminals, a terminal control unit is connected between a call control unit and the terminals. The terminal control unit is associated with a memory unit having a group supervisory table for storing a relationship between group numbers and the terminals belonging thereto for message broadcasting. When a destination call message is supplied from the call control unit to the terminal control unit, a group number is analyzed from the destination call message. Then, a number of the terminals belonging to the analyzed group number are selected in accordance with the group supervisory table, and message broadcasting is performed upon the selected terminals.

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Tokyo, Japan

Kiyokazu Otsuka