If you have custom installed set up for your radar detector, you might not want to take the effort to rewire your car to change brands of detectors. However, it is very easy to make a small patch cable that will make Passport, Uniden, and most brands interchange able.
Most radar detectors use the same 4 wire phone cable with a RJ11 connection. In this four wire set up, the middle wires carry the voltage and the ground, so any custom wire should power any detector.
And the outer cables carry data, so the mute button may or may not work. To fix the mute button, all you have to do is swap the outer yellow and back cables.
To do this you can cut your existing wire or make a patch cable.
If you cut the existing cable, all you need to do is swap the outer wires and re-terminate with an RJ11 connector… This is problematic if you have a short wire, worried you might screw it up, cannot move it to another car or might want to keep the option to use the old detector.
So I prefer to make a patch cable. This keeps the existing wires intact and is very easy to do. The best way to do this is to buy a 6P4C socket with pigtail wires.
1) Cut the the wires to size
1-2 inches is ample.
2) Place a shrink tubing over the wire (for cosmetics)
3) Swap the outer wires (usually black and yellow)
4) Place an RJ11 terminal.