Are Retrofit end-of-line resistors (EOLRs) required?

Is it required to have end-of-line resistors (EOLR)? I know that nothing above 5200 ohms is supported, but what about not having a EOLR installed at all (so basically ~0 ohms, but realistically <2-5 ohms from wire resistance).

For background, my panel had a mixture of standard 2K resistors, but a few 3K and 6.2K mixtures for zone doubling. I know that’s not supported, so I can either take them out entirely, or replace them with 2K. What is best?

Anyone have info on this? I have the same question as wojo.

Not hearing anything here, I asked this question via chat with support. It went like this:


Does the Retrofit Alarm Kit require End of Line resistors? My existing door switches do not have any and show just a few ohms resistance.


Hello … please allow me a minute or two to reach out to our advanced team for these concerns.


checking with our team the wiring configuration would indicate that. Resistors can be inline hidden within the walls or visible at the panel but if you do not have any or if you do it should still work with the retrofit kit.


That’s a little confusing to me. I *measured* the resistance of the switches where they used to terminate at the old alarm box. The resistance is just a few ohms. You are saying that *is* compatible as is to hook to the retrofit kit?

I can add resistors if they are needed or preferred but I can’t tell if they are from the manual or articles so far.


correct resistor are not needed to connect to the retrofit kit


Okay. That makes it clear. Thanks!

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I just want to confirm for everyone that I hooked up 5 zones of direct door-switches with NO resistors and it works like a champ. I can confirm that end-of-line resistors are NOT required.

I purchased a 12-way terminal strip and just mounted it inside my old security system box, then connected the doors I wanted to the strip (I cut off any resistors), then connected new wires from the strip out to the Retrofit kit. It works great!