| 摘要 |
The alarm device is arranged to sense an electrical interface signal between two items of equipment; and comprises a timer means arranged to be started by a change in the signal and to delay the indication of an alarm, and a latch means arranged to reset the timer before the indication of an alarm upon reversal of such change, so that transient changes, do not trigger the alarm. The alarm senses voltage levels at (A,B Fig 2) on, for example a carrier detect line, data receive line, or a signal quality line. A plurality of alarms may be associated. The device may reset automatically upon cessation of the alarm condition, or may require manual resetting. LED's, an audible source and a relay provide the alarm indication (Fig 2). <IMAGE> |
