Model MTL5561 is a zone-powered, two-channel interface for use in conventional fire detection systems for protection within hazardous areas.

In operation, the triggering of a detector causes corresponding change in the safe-area circuit.  The unit has reverse input polarity protection, while 'non-fail' earth fault detection on either line can be provided by connecting an earth leakage detector to terminals 3 or 6.  Certified for use in Zone 0, IIC, T4-6 hazardous areas.