| 摘要 |
<p>The burglar alarm system uses a normal telephone in front of which a special unit is situated. The unit includes an electric motor which may be controlled in order to release the buttons, simulating taking the receiver off the hook, and subsequently to dial a number - for example that of the police. The whole assembly is housed in a sound-proof box, with the handset in contact with the output of a cassette player providing a pre-recorded message. The alarm may be triggered by opening a door so that the police may be alerted to a burglary automatically. An alternative arrangement is provided for use with pushbutton telephone sets, using spring loaded plungers to press the buttons.</p> |
