| 摘要 |
PURPOSE:To discover earlier a fault of a subscriber call meter sucy as open wire or line contact of a call meter connected in parallel with a line relay or the like of a subscriber circuit by deciding the increment of a current or a voltage fed from a test equipment. CONSTITUTION:The test equipment A forms a part of a common controller of an exchange leading and testing a line C of a subscriber line. A circuit B to be tested forms a part of the subscriber circuit installed corresponding to each subscriber. A current measuring circuit AM of the test equipment A is measures a digital current and a discrimination and operation circuit DC consists of, e.g., a microcomputer. A resistance RM of a call meter MET is obtained as RM=e/DELTAI- (e/E)I, where I is a current before the contact of mt contact, (e) is the voltage at operation, DELTAI is a current increment and E is a power voltage of a relay L. Open wire or line contact is decided from the value of RM. |
