EOL relay and Reverse polity for Smoke Detectors


New Member
Hi purchased a bunch of DSC FSA-410 BST smoke detectors as well as their PRM-4W voltage reversing module. The module gets a signal from the elk panel to reverse power to the smoke detectors, thus turning on their sounder. This all works.

The problem is the EOL relay that goes on the last detector that I purchased is a "rm-1" from DSC. This has a diode across the +/- for the coil that prevents reverse polarity, so this doesn't work when the polarity is reversed. If I cut the diode out, the relay functions ok with either normal or reverse polarity, but I wonder about the back EMF affecting the PRM-4W when the relay is deengergised. The instructions for the smoke detectors show a "RM-2" relay. but I cant find any of those on the web for sale.

I called DSC and they said go away, since I am not a dealer. I called one of their distributers and they recommended a EOLR1 from System Sensor. I can buy these but I have the following questions.

How is this EOLR1 different from the "RM-1" relay from DSC? BTW, I took the foam tape off the RM-1 relay and saw that it is a JS1-12v relay, which sells for about $1 from an electronics store compared to the $15 I paid for it through an alarm store.

Will cutting out the diode for the RM-1 (JS1-12v) adversely affect the smoke detectors/PRM-4W module?

Any other relay recommendations?