Hitachi, Ltd.

Keiko Takahara

Naoko Iwami

Susumu Matsui

Kazuma Yumoto

Tohru Hoshi

Toshiaki Koyama

Noriyuki Tanaka

A voice communication system, which is connected to a LAN to which communication terminals are connected and to a public network to which telephones are connected, is provided with a communication server between the LAN and public network having different protocols from each other. The communication server enables a voice communication between a telephone on the public network and a communication terminal connected to the LAN by performing processing similar to that for a voice communication between two communication terminals connected to the LAN. The communication server determines whether an address of the other party inputted by a user is a communication terminal address or a telephone number, and transmits a voice communication request to a communication terminal of the other party when the address is a communication terminal address. When the address is a telephone number, the user acquires the communication terminal address of the communication server, and transmits a voice communication request to the communication server. Thereafter, the voice communication processing is performed through the communication server.

Voice communication system and voice communication method

A voice communication system, which is connected to LAN to which communication terminals are connected and to a public network to which telephones are connected, is provided with a communication server between the LAN and public network having different protocols from each other. The communication server enables a voice communication between a telephone on the public network and a communication terminal connected to the LAN by performing processing similar to that for a voice communication between two communication terminals connected to the LAN. The communication server determines whether an address of the other party inputted by a user is a communication terminal address or a telephone number, and transmits a voice communication request to a communication terminal of the other party when the address is a communication terminal address. When the address is a telephone number, the user acquires the communication terminal address of the communication server, and transmits a voice communication request to the communication server. Thereafter, the voice communication processing is performed through the communication server.

A communication system and communication method adapted so that the user of one of the communication terminals can more easily communicate with another one connected to the internet through the public network. Connection management servers for relay and manage the communication are provided at nodes between the internet and the public network. Each of the connection management servers assigns an IP address to the communication terminal connected to the internet through the public network, and registers the IP address and the telephone number. When receiving a communication request, the connection management server specifies a communication route to the communication terminal on the basis of the telephone number of the called-side communication terminal set in the communication request. The server checks if the called-side communication terminal is connected to the internet on the basis of the above registration. If it is connected to the internet, the server relays the communication request. If it is not connected thereto, the notice that it is not connected is transmitted to the calling-side communication terminal. If it is not connected yet, the server regards the called-side terminal as having its telephone connected to the telephone channel, and causes speech transmission between that telephone and the calling-side communication terminal.

Communication method and communication system

A communication system which can communicate with a party user even when an originator user of a communication terminal does not know the terminal address of a communication terminal of the party user with whom the originator user wants to communicate. When its own user A does not know the terminal address of a communication terminal of a user B, a communication terminal of the user A sends an outgoing file having its own terminal address stored therein as an electronic mail directed to the user B. When receiving the outgoing file as the electronic mail, the communication terminal of the user B displays an icon on its display unit to prompt the user B to enter an instruction of performing reply communication. In response to it, when the user B clicks a mouse on the icon, the communication terminal of the user B can perform the reply communication to the communication terminal corresponding to terminal address stored in the outgoing file.

Communication system using electronic mail

A multimedia mail system and a method thereof generates a message including comments or notes on a background picture using voice and drawing data. The message is sent to a destination terminal using a mail system, and then is regenerated. The voice and drawing data of the received message is synchronized in the same time relation as that used for generation of the message.

Image voice synchronized multimedia mail system and method thereof

A communication system having a plurality of communication terminals which perform data communication with each other through a communication network. Each communication terminal includes a refusing time zone registration unit for registering a time zone in which the communication terminal will not accept a communication request from the other communication terminals, a present time acquisition unit for acquiring a present time when a communication request is received from a communication request transmitting terminal, and a judgment unit for judging whether the communication request has been received during the registered time zone by comparing the acquired present time to the registered time zone. The communication terminal further includes a communication refusing signal issuance unit for issuing a communication refusing signal automatically to the communication request transmitting terminal when it is judged that the communication request has been received during the registered time zone.

Communication system distributing packets according to commands acquired

In a video communication system including a sending terminal and a receiving terminal connected via a packet switching network, a receiving terminal which has detected loss of a video packet sets a video output into a freeze status and transmits a refresh request command to the sending terminal. Upon receiving the refresh request command, the sending terminal requests a video coder unit to execute refreshing and transmits a series of video packets beginning from an INTRA frame. Upon receiving a packet of the INTRA frame, the receiving terminal releases the freeze status and restarts video information decoding.

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Kawasaki, Japan

Keiko Takahara