A method for automatic audible alarm origination locate, comprising the steps of: providing an input-output bus coupling together a spatially diverse plurality of hazard detection and alarm devices (102a, 102b... 102n); monitoring a hazard detector within each of the plurality of hazard detection and alarm devices (102a, 102b... 102n) and if a local alarm signal is detected from the hazard detector of one of the plurality of hazard detection and alarm devices (102a, 102b... 102n), making the respective device a master device and asserting a second logic level on the input-output bus; detecting when the input-output bus at a first logic level goes to a second logic level by the remaining hazard detection and alarm devices (102a, 102b... 102n); determining by each of the remaining hazard detection and alarm devices (102a, 102b... 102n) if the second logic level has been asserted on the input-output bus, and if so, then determining by each of the remaining hazard detection and alarm devices (102a, 102b... 102n) whether they are in a local alarm condition or whether they are not in the local alarm condition, wherein each one that is in the local alarm condition is designated as a follower device and each one that is not in the local alarm condition is designated as a slave 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 to synchronize groups of alert tone pulses from the master, follower and slave devices, wherein alert tone pulse groups from the slave device will only occur when the input-output bus is at the second logic level and wherein the master device asserts the first logic level on the input-output bus periodically for at least one group of alert tone pulses. providing an input-output bus coupling together a spatially diverse plurality of hazard detection and alarm devices (102a, 102b... 102n); monitoring a hazard detector within each of the plurality of hazard detection and alarm devices (102a, 102b... 102n) and if a local alarm signal is detected from the hazard detector of one of the plurality of hazard detection and alarm devices (102a, 102b... 102n), making the respective device a master device and asserting a second logic level on the input-output bus; detecting when the input-output bus at a first logic level goes to a second logic level by the remaining hazard detection and alarm devices (102a, 102b... 102n); determining by each of the remaining hazard detection and alarm devices (102a, 102b... 102n) if the second logic level has been asserted on the input-output bus, and if so, then determining by each of the remaining hazard detection and alarm devices (102a, 102b... 102n) whether they are in a local alarm condition or whether they are not in the local alarm condition, wherein each one that is in the local alarm condition is designated as a follower device and each one that is not in the local alarm condition is designated as a slave 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 to synchronize groups of alert tone pulses from the master, follower and slave devices, wherein alert tone pulse groups from the slave device will only occur when the input-output bus is at the second logic level and wherein the master device asserts the first logic level on the input-output bus periodically for at least one group of alert tone pulses.