Abstract: A method of communicating through a passive optical network (PON) that improves the efficiency of the network with low cost child apparatuses having only simple functions. A parent apparatus provides the child apparatuses with a multi-frame standard signal, and a child apparatus transfers asynchronous information as a frame of variable length, as it is, at a time delayed from the multi-frame standard signal by a time period designated by the parent apparatus. Since the asynchronous information does not need to be divided into pieces to which a frame header is attached, the efficiency of the uplink channel is increased.

Abstract: A method of communicating through a passive optical network (PON) that improves the efficiency of the network with low cost child apparatuses having only simple functions. A parent apparatus provides the child apparatuses with a multi-frame standard signal, and a child apparatus transfers asynchronous information as a frame of variable length, as it is, at a time delayed from the multi-frame standard signal by a time period designated by the parent apparatus. Since the asynchronous information does not need to be divided into pieces to which a frame header is attached, the efficiency of the uplink channel is increased.

Abstract: In a method, an apparatus, and a system for a bandwidth control, a packet is held in a buffer, the held packet is read at a line bandwidth, and a read timing of a next packet is controlled, based on a packet length of a counted packet in order that a difference between the line bandwidth and a setting bandwidth assumes a packet interval. Also, by a flow control combined therewith, a bandwidth control is realized as a system without discarding any packet or with a low packet discarding rate.

Abstract: In a wireless LAN system having two or more master stations each connected to a wired LAN and a plurality of slave stations each connected to a terminal for wirelessly sending and receiving signals to and from the master station via a prescribed channel, each master station is provided with a table for managing the state of channel use. The master station has a LAN controller which periodically notifies the other master station of the state of use of its own channel via a notification packet. Upon receiving a notification packet sent periodically from the other master station, the LAN controller stores the state of use of the channel of the other master station, of which it has been notified by the notification packet, in the channel management table.

Abstract: A mobile user station periodically searches for a connectable access point and stores the address of a connectable access point that has been found in a master-station management table. When the mobile user station moves from one cell to another under these conditions, the state of communication with the old access point deteriorates. When the state of communication with the old access point deteriorates to such a degree that it becomes necessary for the mobile user station to connect to a new access point, the mobile user station sends a connection request to the access point stored in the master-station management table and performs communication via the new access point. As a result, when connection to a new access point becomes necessary owing to movement of the mobile user station between cells, the changeover between access points can be performed quickly without searching for an access point.

Abstract: A master station detects the strength of a signal received from a slave station and, on the basis of the signal strength of the receiving signal, decides a transmission timing at which frame contained in the signal is to be sent to a backbone LAN. When the transmission timing decided arrives, the master station determines whether a carrier is present on the backbone LAN. The master station discards the frame from the slave station, and therefore does not send it, if the carrier is present. If the carrier is not present on the backbone LAN, the master station sends the frame to the backbone LAN. Thus, interference between adjacent cells does not occur even when each of a number of master stations send signals to and receive signals from a slave station by using the same channel.

Abstract: A keep call back device for connecting calls between subscribers includes a first call establishing portion for establishing a first call by connecting a call received from a calling terminal to a called terminal when it recognizes the call from the calling terminal which is able to respond to a call from one terminal without ending communication with another terminal during communication with another terminal, a second call establishing portion for establishing a second call by placing a call to the calling terminal after the first call has been established, and a call releasing portion for releasing the first call by disconnecting the same when the second call is established.

Abstract: A LAN-WAN-LAN communication method and apparatus for performing communication between a LAN on a transmitting side and a LAN on a receiving side via a wide area network within limits of an allocated band includes a demultiplexer/multiplexer unit for demultiplexing data, which has been received from the LAN on the transmitting side, into data constituting the smallest units of information and transmitting this data via a plurality of lines. Then, data, which is sent to the receiving side via each line, is multiplexed on the receiving side and the multiplexed data is sent to the LAN on the receiving side. A traffic monitoring unit is provided for monitoring traffic between LANS. A band is obtained, which is required for communication between LANs based upon the traffic. Communication between LANs is performed by increasing, decreasing or maintaining the number of lines, which are used in communication between LANS, based upon the obtained band.

Abstract: An optical transceiver is coupled to a U-shaped optical bus and to data terminals employing CSMA/CD.

Abstract: A transmitting data processing system used in a node of a data transmitting system, such as a local area network, applied in a wide area using a relatively long range transmission line and a plurality of the nodes on the transmission line for relaying a frame comprising a preamble pattern and transmitting data. A beginning part of the preamble is dissipated or lost in each node when a clock signal is extracted from the preamble pattern. The dissipated part is restored in the node by adding a newly generated preamble signal having a time duration being substantially equal to the time duration of the dissipated part at the beginning of the dissipated preamble pattern after sensing the dissipated preamble pattern, or by replacing the dissipated preamble pattern with a newly generated preamble pattern equal to a standard preamble pattern after sensing a carrier of the frame.

Abstract: An optical communication system including repeaters which return a preamble signal to the receive line as soon as it detects a carrier on the transmit line of a single line optical bus. Therefore, transmission equipment can confirm data transmission quickly because the time delay between data transmission and its confirmation is decreased. The repeater also monitors a time delay associated with the return through a return loop of the transmitted data, and produces and transmits a failure signal when the time delay is longer than a predetermined value. The system also includes an optical transceiver connected between the optical bus and the transmission equipment which converts optical signals into electrical signals and visa versa and also adds the preamble signal to the front of data to be transmitted.