Patent ID: 7830252

Claim:
An alarm unit, comprising: a flash circuit having a strobe for generating a flash; an audio circuit having at least one of: a horn or a buzzer for generating an audio warning signal; an application specific integrated circuit (ASIC) coupled to said flash circuit, and to said audio circuit, for triggering said audio warning signal, wherein said ASIC selects an audio frequency for said audio warning signal, wherein said audio frequency being a sweep frequency of approximately 2500 Hertz (Hz) to 4000 Hz, and a sync pulse detection circuit coupled to said ASIC for detecting a sync pulse, wherein the sync pulse is detected if a voltage drops to a logic low on a pin of the ASIC for greater than a predetermined time period, wherein the detecting of the sync pulse causes the strobe to generate the flash and causes the horn or the buzzer to generate the audio warning signal in a code 3 pattern, wherein the code 3 pattern comprises an approximately 0.5 second period of silence and an approximately 0.5 second period of sound repeated three times followed by an approximately 1.0 second period of silence.