I bought a house and just replaced 8 hardwired smoke alarms that were 10+ years old units like this. They had the typical high voltage red/white and red interconnect wires, with thick wires.
However there's a 9th unit in my house that looks very different and has a different wiring configuration. It is only a few inches away from one of the other units.
The wiring / size of wires / voltage is different on this one.
What is the purpose of having this separate setup? Should I replace it with a similar unit (e.g. same model number)? What specifically would I be searching for if I wanted to find an alternative unit to replace it with?
There is a wired alarm system in the house, does this unit tie into it somehow and maybe that's why the wiring is different? If so does that mean that only this detector is tied into the alarm?