A method for testing the signal margin of an alarm system during installation of the alarm system and during the alarm system supervision time. The alarm system comprises a plurality of remote transmitting devices and a receiver/control unit. The receiver/control unit comprises a receiver with at least...http://www.google.com.hk/patents/US6087933?utm_source=gb-gplus-share專利 US6087933 - Antenna switching for amplitude degradation during supervision and installation of wireless security systems
