摘要:
A method is provided for managing virtual networks wherein switching hubs, each having ports to which nodes are respectively connected and having a bridging function, are interconnected via an ATM network, and predetermined ones of the ports of the switching hubs are grouped in order to construct virtual LANs. Data from a source node is transmitted to nodes belonging to the same group as the source node. A VLAN server, which stores MAC addresses of these nodes and VLAN identifiers in association with each other, is connected to the ATM network and collectively manages all nodes by means of the MAC addresses. The switching hub makes an inquiry for a VLAN identifier, and reconstructs or modifies the VLAN in accordance with a VLAN identifier responded from the VLAN server.
摘要:
A multipath transmission system for an automobile according to the present invention comprises a plurality of multiplex transmission units connected in parallel with each other to one common bus. Each transmission unit is assigned to one of groups in which various devices attached to the automobile are classified. The transmission unit includes a sending circuit for transmitting the multiple signals from the devices in the group concerned to the other units through the bus. The system further comprises a power source for always applying electric power to the sending circuit of at least one of the multiplex transmission units. Only that multiplex transmission unit to which the electric power is always applied is provided with a bias circuit which sets the potential of the multiple signals on the bus when the multiple signals are supplied from the sending circuits of any multiplex transmission unit to the bus.
摘要:
A device for controlling the current consumption of a power supply which applies a voltage to a transmission control circuit for transmitting a transmission signal with respect to a transmission line is provided. A power supply stabilizing circuit for stabilizing a voltage applied from the power supply; an amplitude detection circuit for detecting a transmission signal input from the transmission line; a switching circuit for interrupting application of a voltage from the power supply stabilizing circuit to the transmission control circuit; and a control circuit for controlling the open/closed state of the switching circuit according to the presence or absence of a transmission signal detected by the amplitude detection circuit are provided, and only when the amplitude detection circuit has detected the transmission signal, the control circuit sets the switching circuit into the closed state so as to permit a voltage to be applied to the transmission control circuit. When no transmission signal is transmitted, application of an unnecessary voltage to the transmission control circuit is interrupted, thereby reducing the current consumption.
摘要:
A multipath transmission system of this invention includes a plurality of multiplex nodes connected in parallel to three common signal transmission lines. The multiplex node includes a transmission control circuit which is allotted to a corresponding one of devices, receives a multiplex signal from the device in response to a transmission request of another multiplex node and transmits the multiplex signal to the signal transmission line. It includes a voltage detection circuit for detecting a voltage generated in at least one of the transmission lines, a reception control circuit for specifying the transmission state of the signal transmission line according to a voltage detected by the voltage detection circuit, a communication control device for communicating with the multiplex nodes to detect fault, and a voltage setting circuit for changing a voltage of the signal transmission line when fault is detected by the communication control device.