| 摘要 |
<p>An alarm unit (20) which conveniently forms part of an alarm system is adapted when in operative condition, and when the alarm system of which it forms part is armed, to be caused by a trigger signal produced by the alarm system to generate an audio and/or visual message advising of activation of the alarm system. Thus, if the alarm system is armed or disarmed erroneously by an authorised user, or if an authorised user inadvertently triggers the alarm system, he will be alerted by the advisory message to take appropriate remedial action.</p> |
