A ring network of workstations interconnected on a single simplex ring is converted to duplex communications on the single ring by placing two transceivers in each workstation and adding a duplex conversion device between each workstation and its ring terminal box. One of the transceivers receives and retransmits signals in a clockwise direction around the ring; the other transceiver receives and retransmits signals in a counter-clockwise direction around the ring. The clockwise and counter-clockwise signals are superimposed on the ring but are isolated at the workstations by the duplex conversion device.
A broadband modem hybrid transformer couples a broadband modem to a plain-old-telephone (POTs) line. The hybrid includes a full bridge having an impedance matching network to reduce the transhybrid attenuation of the hybrid. The second matching network(s) include various resistive and reactive components which together provide an impedance value selected based upon the impedance of the telephone line typically reflected into the primary windings of the transformer. The matching network increases the transhybrid attenuation of the hybrid, and thus reducing the amount of noise which couples from the modem transmit circuit to the modem receive circuit through the hybrid.
1:N duplex communication equipment which has a host device and slave devices interconnected in a ring form is disclosed. In the equipment, the path distributing part 3 of the host device transmits an identical path to the two-way transmission line of the ring, and a path selecting part 4 selects a normal one of paths from the two-way transmission lines. The path distributing part 6 of each slave device distributes a path from one transmission line to the other transmission line and the path selecting part. A path selecting part 5 selects paths sent from the host device through the two-way transmission lines from the path distributing part. A path selecting part 8 selects a path sent from another slave device through the two-way transmission lines and outputs this path to a transmitted data control part 9. The transmitted data control part 9 selects data to be transmitted to the host device from received data in the selected path and transmitted data of its own device. A path transmitting part 10 transmits data from the transmitted data control part through the paths of the two-way transmission lines. Thus, 1:N bi-directional communication is performed by a smaller number of paths.
A method of detecting the network configuration of a communication network in which a plurality of nodes are connected in a ring form, comprises the steps of; enabling a node of the plurality of nodes to store its own node identifier in a specific position of an identifier storing area of a frame, and transmitting said frame along the network in the same direction; enabling each of the plurality of nodes to store its own node identifier in the identifier storing area of said frame and again transmitting said frame in the same direction, and abandoning said frame, according to contents of said frame received from the adjacent node; and enabling each of the plurality of nodes to recognize an arrangement of the plurality of nodes on the communication network, on the basis of contents of the identifier storing area of said frame constantly transmitted and received on the communication network.
A duplex communication path switching system provided at each of nodes connected by a communication path which is formed of clockwise and counterclockwise transmission lines in a ring network. The duplex communication path switching system includes a checking circuit for checking whether or not each of a plurality of units of the signal received from each of the clockwise transmission line and the counterclockwise transmission line is normal, and a switching circuit for switching the communication path between the clockwise transmission line and the counterclockwise transmission line based on checking results obtained by the checking circuit so that units which are normal are selected from the signals. Each of the plurality of units of the signal has a constant speed and is provided with frame information defined for the signal transmitted through the communication path, the frame information being used to divide the signal into the plurality of units.
A method for selectively modifying an information signal at a remote site in a telecommunications system having a head end and a number of remote sites connected to form a ring. An initiation signal is received at a head end. The initiation signal indicates when to start modifying the information signal. Further, the method retrieves at least one stored modification signal. The method also transmits the modification signal to at least one selected remote site over a packet ring network of the telecommunications system. The packet ring network includes ring switches that self-learn the location of network devices based on addresses in packets processed by the switches and which learn that addresses of network devices associated with other ring switches are reachable out of at least one ring port of the ring switch. The information signal is modified with the modification signal. The method also detects the end of the modification signal and ends the modifying of the information signal.
