SUPERVISORY CIRCUIT OF REPEATER

摘要

PURPOSE:To distinguish the fault of a repeater from that of a line and to detect these faults by using a low frequency signal having a specific pattern and DC for a test. CONSTITUTION:A specific code is transmitted from a remote place through a line. When a repeater 2k detects the code, switches SW6k, SW7k are inverted. Data from the remote place is returned to the remote place through a line terminal Pk'. When DC is applied from the remote place to the line, a relay 3k is actuated. Consequently, contacts SW1k-SW5k are inverted. Therefore, the repeater 2k is by-passed and the line is directly connected through a transformer. A direct current flowing into the relay 3k is returned to the remote place through the line terminal Pk'. A built-in power supply 4k applies DC to the succeeding repeater.