Patent ID: 8922362

Claim:
A method for temporal horn pattern synchronization, comprising the steps of: monitoring an input-output bus coupling together a spatially diverse plurality of hazard detection and alarm devices; detecting when the input-output bus at a first logic level goes to a second logic level; determining if the second logic level remains on the input-output bus for a first time period, wherein if so, then determining which ones of the plurality of hazard detection and alarm devices are in a local alarm condition and which other ones are not in the local alarm condition, wherein the ones that are in the local alarm condition are designated as follower devices and the other ones that are not in the local alarm condition are designated as slave devices, and if not, then determining when one of the plurality of hazard detection and alarm devices is in the local alarm condition; making a first one of the plurality of hazard detection and alarm devices in the local alarm condition a master device; asserting the second logic level on the input-output bus with the master device; asserting the first logic level on the input-output bus with the master device for short times between asserting the second logic level thereon; and synchronizing groups of alert tone pulses from the master, follower and slave devices.