| 摘要 |
The first aspect of the invention is a method for ensuring that an adequate signal margin exists between an alarm system's central control unit and its wireless devices during normal operation. The wireless devices include a remote dialer, a remote siren, and a user interface device. During installation of the alarm system, the installer locates the central control unit and the wireless device being installed. An alarm condition is simulated, and an alarm message is transmitted by the central control unit's transmitter at a power level lower than the power level during normal operation. The wireless device indicates if it has successfully received the alarm message, or if it has not, it is relocated and the alarm condition is simulated again until the wireless device indicates that it has received the alarm message. The installer knows there will be adequate signal margin between the central control unit and the wireless device during normal operation when the low power alarm message has been received by the wireless device. Also, the reduced central transmitter output power may be coincident with reduced central receiver sensitivity allowing the installer to ensure adequate system signal margin in both up and down links. The second aspect of the invention is a self testing wireless data communications system suitable for use with an alarm system, the transmitting element of the communications system capable of transmitting at two different output power levels. If the message is a supervisory message, it is transmitted at a lower power level than an alarm message, in order to ensure that non-supervisory alarm messages are received with an adequate signal margin. <IMAGE> |
