Abstract: It is left to a communication terminal side to judge whether to switch communication, and appropriate switching is not performed if a communication terminal does not have a function to switch communication based on the quality of communication. A communication apparatus comprises: a data signal transmitting unit that transmits a data signal to a communication terminal; a control signal transmitting unit that transmits a control signal for establishing communication with the communication terminal; and an area control unit that restricts, to a partial area within a communication possible area that a radio wave including the data signal can reach, a communication establishment possible area that a radio wave including the control signal can reach.

Abstract: It is left to a communication terminal side to judge whether to switch communication, and appropriate switching is not performed if a communication terminal does not have a function to switch communication based on the quality of communication. A communication apparatus comprises: a data signal transmitting unit that transmits a data signal to a communication terminal; a control signal transmitting unit that transmits a control signal for establishing communication with the communication terminal; and an area control unit that restricts, to a partial area within a communication possible area that a radio wave including the data signal can reach, a communication establishment possible area that a radio wave including the control signal can reach.

Abstract: The present invention aims at providing an ascending transmission speed controlling method and a communication system in an ATM-PON (asynchronous transfer mode-passive optical network), in which ascending transmission speeds on the PON are dynamically allocated corresponding to actual transmission states of communication channels of a best effort type, to thereby effectively utilize respective bands.

Abstract: By transmitting an analog CATV signal output from a CATV-HE (CAble TeleVision-Head End) to an HDT (Host Digital Terminal), an analog transmission channel for transmitting the analog CATV signal to an ONU (Optical Network Unit) is included in a path housing a digital transmission channel for transmitting a digital service signal for individual distribution service to the ONU. Furthermore, a digital service signal for multicast service is modulated and converted into an analog service signal by a modulator in the HDT. Then, the converted signal is mixed with the analog CATV signal, and transmitted to the ONU. Accordingly, each of the ONUs is equipped with only a built-in modulator for modulating the digital service signal for individual distribution service.

Abstract: A media information distribution service system, such as a video-on-demand service system, is disclosed which, even if the capacity of a line is small and the number of lines connected to a media server, such as a video server, has to be increased accordingly, permits an uneconomical increase in the number of line circuits in the media server to be checked. In the system, a subscriber group that a distributor accommodates can be associated with a plurality of distributor-side paths on a distributor-side line. Each of the distributor-side paths is connected to a respective one of server-side paths on separate server-side lines connecting the media server and an exchange. In sending media information to a subscriber group, an in-server path control unit installed in the media server is permitted to select a free one out of server-side paths on server-side lines allocated for that subscriber group and activates a line interface corresponding to the free server-side path.

Abstract: The invention provides a picture phone terminal and an exchange for use, for example, with a picture phone interrupt service system for a broadband ISDN which makes it possible to confirm, when an incoming call arrives, during communication between a plurality of picture phones, at one of the picture phone terminals from a third picture phone terminal, the incoming call during the communication without disturbing the communicating condition at present.

Abstract: The present invention, in an ATM (Asynchronous Transfer Mode) which houses data in fixed length packets known as cells and transmits them to a receiving end, has as its object to provide a technology which can relay and transmit, within an ATM exchange, overhead section control information and can effectively perform maintenance and management of a communication network. Also, the order wire apparatus of the present invention comprises a network end device between a subscriber terminal and an exchange, this network end device comprising a frame data preparing means for simultaneously mapping communication data transmitted from a subscriber terminal into the payload section of frame data and mapping control information input by a maintenance worker into the overhead section of the frame data.

Abstract: A length of an I field of an I frame in the data link layer is controlled in accordance with a rate of cells lost in an ATM layer. The loss rate of cells is calculated by watching sequence numbers included in the cells in an ATM adaptation layer.