Abstract: An interface apparatus of an ATM/STM coexistence network system includes a first converter for converting a first input signal of a synchronous transfer mode into a signal with a cell format having an additional address for an asynchronous transfer mode and outputting the signal with the cell format as a first asynchronous transfer mode cell and a second converter for extracting an asynchronous transfer mode cell from a second input signal in which the asynchronous transfer mode cell is multiplexed in the synchronous transfer mode and outputting the extracted asynchronous transmission mode cell as a second asynchronous transmission mode cell. The interface apparatus further includes an output-destination controller for determining output destinations in accordance with addresses shown in the first and second asynchronous transfer mode cells.

Abstract: A system for protecting a remote power supply for supplying power to an optical subscriber network, via a pair of power supply lines, from a remote power supply apparatus, being provided with power supply branch apparatuses inserted into the power supply lines in correspondence with each power receiving circuit respectively mounted in subscriber transmission nodes. Each of the power supply branch apparatuses comprises relay contacts inserted into its own power supply branch lines connected between the power supply lines and its own power receiving circuit, and a relay energized by an overcurrent detector or first and second communication units to change over the relay contacts. The relay contacts are opened and closed subscriber by subscriber sequentially to detect a faulty portion, and thereafter, the power is fed again selectively to the subscribers which have not experienced the fault.

Abstract: The present invention relates to a surge protector for suppressing a surge voltage generated on transmission lines, having an object to prevent system shut-down by grounding detected by terminal equipment at the time of suppressing a surge, using a discharge tube for suppressing intermittently a surge voltage.

Abstract: A transmission line monitoring system for monitoring the quality of a transmission line along which a plurality of repeaters are equipped. A monitoring line is equipped along the transmission line for transmitting a signal for collecting information on the quality of the above transmission line. A plurality of monitoring units are respectively provided corresponding to the above plurality of repeaters. A centralized monitoring unit sends an instruction which includes information on a section of the transmission line which is to be tested, through the monitoring line, and receives the above information on the quality of the above section of the transmission line, which is sent from a monitoring unit responding to the above instruction through the above monitoring line. Each of the monitoring units receives the above instruction through the communicating circuit, and determines whether or not its own monitoring unit corresponds to a repeater at the beginning or the end of the section, by the control circuit.

Abstract: A supervisory system for a primary group digital transmission line wherein a terminal repeater transmits, over a supervisory line, address information designating an intermediate repeater and line within the intermediate repeater to be monitored while the line is in a normal, in-service condition. The terminal repeater and intermediate repeaters are cascade connected by way of the supervisory line. The terminal repeater and each of the intermediate repeaters include amplifiers that receive and send information along the transmission line, and have a monitor output. The monitor output is processed by an error monitor within the terminal repeater and in each of the intermediate repeaters and the results of the error monitoring provided to the supervisory line in response to polling by the terminal repeater.