Patent ID: 7522037
Filing Date: 2009-04-21
Classification: G08B

Abstract:
1. In a method of forming and transmitting signals from a fire alarm unit to a receiving-monitoring instrument via a communication line with the aid of a transmitting device which is a part of the fire alarm unit, the method comprising self-testing operability of the fire alarm unit and determining a value of a monitored fire factor, the improvements characterized in that the fire alarm unit is additionally provided with a logic device for comparing the value of the monitored fire factor with a permissible value, and the signals including (1) a first signal indicating the operability of the fire alarm unit as judged from the self-testing and (2) a second signal indicating that the permissible value of the monitored fire factor has been exceeded are transmitted in an analog mode such that simultaneous transmission of the first and second analog signals carrying different information is performed via the same communication line.