The System 3 supplementary relay module (Model SR-35) from Siemens ─ Fire Safety is designed to activate or deactivate external circuit controls, such as: door releases, fan shutdown and other fire-related equipment. Model SR-35 contains eight (8) independent relays with SPDT contacts rated at 2 Amps max. Each relay can be selected to operate either in a high-level signal from appropriate System 3 modules or via an open-collector input signal commonly found in Siemens ─ Fire MXL and SXL®-EX fire systems. The position of actuation-mode headers on each relay determines high or low-level signal activation.