I've been searching for the past week here on NASIOC, and on mp3Car.com, radardetectors.net, rallitek.com, and google for pinouts or a schematic of the SmartCord that has the mute button and flashing alert LED for my Passport 8500. I want to hardwire my SmartCord like other installs I've seen around the forum, but don't want to destroy my SmartCord in the process.

Couldn't find a damn thing other than red wire = +12V and green = ground, so I took mine apart and reverse-engineered it :devil: to come up with this:

http://i18.photobucket.com/albums/b121/cmags/SmartCordSchem.gif

Figured that after all my searching I'd get this info out to the forum. I'm 99% sure its correct, though I need to find a 680K resistor before I can build my own. I'll update this thread when I do.

Thanks, and let us know how it turns out. I have the Bel RX65 which is virtually the same and I wanted to see how it was setup.

offset

Ok, I put the thing together, but still couldn't find a 680K resistor. Instead I used a 470K and 2 100K's in series to make 670K, which I figured was close enough. Seems that it may not be:

The power and alert LED's work properly, and the detector seems to be running fine, but when the detector goes off, the mute button doesn't work (which was the entire point of making this instead of just applying +12V and ground to the detector).

Does anyone know if that difference of 10K could cause that? (10K is like 1%~2% difference - within the 5% tolerance of the original resistor) Maybe there's some real engineers out there that could take a quick peek at it?

I doubt it, but there's no way to tell without having knowledge of the rest of the circuit. Why not just add a 10K in series to bring the value to 680K? 10K is an easy value to find.

Figured out the problem: I mis-read one of the resistors on the SmartCord as 1K when it was 10K (saw orange as red in the low light of my office cubicle). Just replaced it in the lab and will test it out on the ride home tonight. I did a side-by-side DC comparison between the two boards and they seem to be working just like eachother, but I have no radar source in the lab so I'll have to give it a live test. I'm pretty confident that was the problem.

Here it is:
http://i18.photobucket.com/albums/b121/cmags/HomeMadeSmartCord.jpg

Now I just have to figure out where to mount the LED's and mute button and run the phone cord up to my Escort, and I'll still have my lighter-socket SmartCord to bring with me when I'm in any other car! :banana: