An alarm system, comprising a smoke detector, a smoke detector output relay, a recording switch, a microphone, a digital recording and a play back device, a timer/pulse generator, a pulse counter, a number of speakers, an amplifier and an alarm tone generator, and the method of operation of the alarm...http://www.google.es/patents/US5663714?utm_source=gb-gplus-sharePatente US5663714 - Warning system for giving verbal instruction during fire and method of operating the warning system
Warning system for giving verbal instruction during fire and method of ...
