| 摘要 |
<p>A network termination unit (20) for connection to a telephone line (12, 14) at a predetermined demarcation point thereof for sequentially simulating a plurality of fault conditions to allow a diagnostic routine to be performed on the telephone line at a remote location from the demarcation point. The network termination unit (20) comprises a plurality of semiconductor switches (34, 36, 38, 40, 42, 43) electrically connected to conductors of the telephone line to establish a network of electrical paths capable of altering the electrical condition of the telephone line when caused to assume a state of conduction. A logic module (32) causes the switches to assume either a closed or an opened condition in accordance with a predetermined sequence established by a hard-wired program.</p> |
