| 摘要 |
PURPOSE:To prevent complicated control, by controlling a subscriber line lead- in switch with turning-on of a switch to which a howler transmitter is connected, in addition with turning-on of two switches for normal test. CONSTITUTION:In testing a subscriber line, first a switch in a subscriber trunk SUB is operated to disconnect the line from a time division switch TDSW. The incoming side of the subscriber line lead-in switch ASW is connected to each SUB and the outgoing side is connected to each tester of subscriber lines LTU and a howler trunk HOWT. In each test of the subscriber lines, relays (a), (b) in the ASW are activated. In case of howler test, a relay is energized while the relays (a), (b) in the ASW are turned on. That is, subscribers listen to howler tone with duplicated connection. Further, the maintenance personnel listens to a howler back tone through the test device LTU of subscriber lines. |
