System Sensor 2151 Compatible with Simplex 4004?

I’m assuming the compatibility is fine, but since the smoke detector is modern and the panel is from 1999 I just wanted to check before I buy. I was gonna buy the head and a B110LP base.

As long as it’s a conventional smoke detector and the panel zones give out DC power (which the 4004 does) it should be fine. Panels from 1980 and up use DC power so there should be no problem. The only thing i’d worry about is what alarms you connect to the NAC’s. People have fried those panels when connecting some alarms. It happened to msj191961 on YouTube. https://www.youtube.com/watch?v=sbjOerYtoMs