ONE-LOOP04 and ONE-LOOP10 products series are expansion modules created for ONE Systems, to add an extra communication port. That makes possible the ONE-500 interconection, performing an united system up to 60 zones. The ONE-LOOP module provides redundant communication so that the system is monitored and can be controlled according to EN54 requirements. There are two available models that allow systems consisting of up to 4 units and 24 zones with the ONE-LOOP04 model or up to 10 units and 60 zones with the ONE-LOOP10 model.