| 摘要 |
<p>A security system comprises a home control unit (43) which is associated with security aware apparatus and provides signalling defining release codes to the security aware apparatus. Security aware apparatus will not work unless or until it receives a valid release code from the home control unit (43). The home control unit (43) communicates with a remote operations centre (not shown) by way of a cellular switching system. The cellular switching system includes means responsive to time delay between signals from the transmitting means of the home control and each of a plurality of receiving cellular aerials to determine a locational data for the home control unit. The location data is transferred to the remote operations centre whenever a request is transmitted by the home control unit.</p> |
