Has anyone encountered a very old fire alarm system that has a seperate 2 wire circuit with an EOL at each device? I am working on an existing fire alarm system that runs 2 wires in(red and black) and 2 wires out to next pull station or to the end of line resistor...but it also has a second circuit ( 2 blue wires) to each pull station with a different eol resistor at each pull station.

Does anyone know what the 2 blue wire circuit is and why there is a EOL at each device?




[This message has been edited by Cinner (edited 08-23-2006).]