There may not be a fixed standard, found some info here
Which might help you . At the simple end of the market it may just be a wire that goes hi in alarm condition - you could check that , more complex units have some form of coms
There may not be a fixed standard, found some info here
Which might help you . At the simple end of the market it may just be a wire that goes hi in alarm condition - you could check that , more complex units have some form of coms