Abstract: A conversion apparatus includes a first interface unit connecting to an asynchronous communication network to receive a packet signal, a signal conversion unit converting the packet signal into an intra-apparatus signal, a packet-discard determination unit determining whether or not any portion of the packet signal is discard, a clock selection unit selecting a reference clock signal, a loss-of-synchronization determination unit determining whether or not a loss-of-synchronization error is occurring in the reference clock signal, an alarm control unit generating one of first, second, and third control signals, a framer generating a frame signal in response to the first control signal, an alarm signal in response to the second control signal, and a synchronous signal in response to the third control signal, and a second interface unit connecting to a synchronous communication network to transmit one of the frame signal, the alarm signal, and the synchronous signal.

Abstract: A gateway device which mutually converts communication protocols among a subscriber network including a base station wirelessly housing a mobile terminal and an Internet Protocol processor to bring an interface from the base station into an Internet Protocol process, a public switched telephone network and a packet communication network, includes a synchronized network terminating unit which terminates the public switched telephone network to generate the in-device signal, a packet network terminating unit which terminates the packet communication network to generate the in-device signal, a subscriber network terminating unit which houses the base station via the interface to which the Internet Protocol process is applied and terminates the subscriber network to generate the in-device signal, and an exchange unit which exchanges in-device signals each generated from the synchronized network terminating unit, the packet network terminating unit and the subscriber network terminating unit.

Abstract: A communication system, a communication apparatus and a terminal accommodation apparatus which use a metallic subscriber line and are a high-speed and inexpensive are provided. The communication system includes a plurality of terminal accommodation apparatuses 200 for accommodating terminals 3c, 3d, a communication apparatus 1 connected to an IP network 4, and digital subscriber lines L3 for connecting the plurality of terminal accommodation apparatuses 200 and the communication apparatus 1. The terminal accommodation apparatus 200 includes a PCM (pulse code modulation) modulator and a subscriber line interface. The PCM modulator converts a voice signal received from the terminal 3c to PCM data. The subscriber line interface transmits data including the PCM data to the communication apparatus 1 via the metallic subscriber line L3. The communication apparatus 1 includes an IP converter 130 for converting the PCM data to an IP (Internet protocol) packet.

Abstract: A conversion includes a first interface unit connecting to a asynchronous communication network to receive a packet signal, a signal conversion unit converting the packet signal into an intra-apparatus signal, a packet-discard determination unit determining whether or not any portion of the packet signal is discard, a clock selection unit selecting reference clock signal, a loss-of-synchronization determination unit determining whether or not a loss-of-synchronization error is occurring in the reference clock signal, an alarm control unit generating one of first, second, and third control signals, a framer generating a frame signal in response to the first control signal, a alarm signal in response to the second control signal, and a synchronous signal in response to the third control signal, and a second interface unit connecting to a synchronous communication network to transmit one of the frame signal, the alarm signal, and the synchronous signal.

Abstract: A radio communication system and a radio base station apparatus which are capable of high-speed transmission and the network synchronization using a metallic subscriber line are provided. The radio communication system has a plurality of radio base station apparatus CS which accommodates a radio terminal PS, a communication apparatus 1 which is connected to a IP network 4, and a digital subscriber line L3 which connects the radio base station apparatus CS and the communication apparatus. The radio base station apparatus CS has a clock unit which generates a clock of predetermined frequency common to each radio base station apparatus CS based on a signal supplied from the communication apparatus 1 via the digital subscriber line L3. The radio base station apparatus CS communicates the data with the radio terminal PS using a radio frame of a time division created based on the clock which the clock unit generates.

Abstract: A communication system, a communication apparatus and a terminal accommodation apparatus which use a metallic subscriber line and are a high-speed and inexpensive are provided. The communication system includes a plurality of terminal accommodation apparatuses 200 for accommodating terminals 3c, 3d, a communication apparatus 1 connected to an IP network 4, and digital subscriber lines L3 for connecting the plurality of terminal accommodation apparatuses 200 and the communication apparatus 1. The terminal accommodation apparatus 200 includes a PCM (pulse code modulation) modulator and a subscriber line interface. The PCM modulator converts a voice signal received from the terminal 3c to PCM data. The subscriber line interface transmits data including the PCM data to the communication apparatus 1 via the metallic subscriber line L3. The communication apparatus 1 includes an IP converter 130 for converting the PCM data to an IP (Internet protocol) packet.

Abstract: A gateway device which mutually converts communication protocols among a subscriber network including a base station wirelessly housing a mobile terminal and an Internet Protocol processor to bring an interface from the base station into an Internet Protocol process, a public switched telephone network and a packet communication network, includes a synchronized network terminating unit which terminates the public switched telephone network to generate the in-device signal, a packet network terminating unit which terminates the packet communication network to generate the in-device signal, a subscriber network terminating unit which houses the base station via the interface to which the Internet Protocol process is applied and terminates the subscriber network to generate the in-device signal, and an exchange unit which exchanges in-device signals each generated from the synchronized network terminating unit, the packet network terminating unit and the subscriber network terminating unit.

Abstract: ATM transmission equipment provided between existing exchange or terminals of carrier equipment that, for example, can emulate existing transmission paths, and also implement T point interfaces for an in-home unit. The ATM transmission equipment detects communication anomalies or extracts maintenance/operation information from data strings on STM lines, such as high-speed digital lines or ISDN lines, and replaces only the necessary information resulting from those extractions or detections with alarm signals. The alarm signals are then transmitted together with information channels to the ATM network via a cell assembler/dissembler. The information channels and alarm information that arrive from the ATM network are rearranged into STM line data strings and output to LT units, DSUs, or terminals.

Abstract: In a radio communication system which is comprised of a plurality of node devices having a radio unit for radio communications in an associated section with a neighboring node device and a management device for managing the respective node devices, the node devices are provided with a GPS device and sends position information about the own node device generated by the GPS device to the management device. The management device generates control information for adjusting an antenna direction and a radio level of the radio unit of the node device according to the position information received from the node device and sends to the node devices, and the node devices performs automatic adjusting control of the antenna direction and the radio level of the own node device according to the received control information.

Abstract: An ATM cell assembly and disassembly device capable of flexibly dealing with various data speeds on STM and ATM sides, and preventing the buffer overflow. In the ATM cell assembly device, the data stored in the buffer are outputted when an amount of the stored data becomes not less than a prescribed data amount sufficient for loading a payload section of each ATM cell, and the ATM cell flow is obtained from the ATM cells assembled from the data outputted from the buffer and empty cells. The buffer can be allowed to output the stored data only when the output permission signal issued in accordance with usage parameter control (UPC) parameters determined at a time of call set up is received. In the ATM cell disassembly device, the output data are stored into the buffer when a currently remaining capacity of the buffer becomes not less than an amount of data loaded in a payload section of each ATM cell, and the STM signals are obtained from the output data outputted from the buffer.

Abstract: In a packet switching system, a plurality of transmitting/receiving interfaces are connected to a single data bus and a clock bus. A clock source supplies clock pulses marking a repeating series of data transmitting time slots to all of the interfaces over the clock bus, each time slot in the series being assigned to a different one of the interfaces. Each interface assembles packet data and an address received from a terminal or office line for transmission over the data bus during the interval of its assigned time slot and receives packet data from the data bus. Each interface extracts packet data addressed to it for transmission to another terminal or office line.

Abstract: A packet communication system suitable for a high speed bus, and a method of controlling the system. A data bus is divided into a control bus for receiving data for contention control and a transmission bus for receiving only communication data including destination data. Each terminal interface transmits the contention control data to the control bus in the transmission cycle prior to transmission of its packet to perform contention control. Thus, exclusive occupation authority of the transfer bus is acquired prior to packet transmission. Each terminal interface finishes the contention control in the cycle prior to the data transmission cycle to previously make a reservation for the use of the bus, and outputs the packet following the DLA onto the transmission bus in the next data transmission cycle.

Abstract: A packet communication system which communicates various communication information such as voice, data or images in the form of a packet and which provides a transmission quality which satisfies both of high instantaneousness and low discard properties and a method of controlling the system. A counter counts the respective numbers of stays of packets in priority-classified buffers. The percentages of output of packets from the respective buffers and both of the percentages of output of packets from and the percentages of input of packets to the respective buffers are controlled in accordance with the counted numbers of stays of packets in the respective buffers and information on the priorities of the packets.

Abstract: When an interrupt request to a control unit occurs, the control unit polls a plurality of interrupt request terminal interfaces to locate which of the interrupt request terminal interfaces has generated the interrupt request. The control unit polls the plurality of interrupt request terminal interfaces in groups of several interrupt terminal interfaces to locate a group to which the interrupt request terminal interface has generated the interrupt request belongs, and polls only the respective interrupt requests terminal interfaces belonging to the located group to thereby locate the generated source of the interrupt request. Each interrupt request terminal interface generates an interrupt request as vector data indicative of contents directly corresponding to each interrupt condition.