PMR to Baehr helmet cable

I recently bought a set of Baehr with built in speaker and microphone. I bought a cable for my Walkman (RKA-01-01), but the real fun would be to connect them to a PMR radio for cheap intercom. So I did a little Sunday afternoon of testing and these are my results. The "Walkman cable" has some piece of electronics in the middle that I didn't pry open and check out, it might simply be a coil to reduce noise, but it could have some significant purpose.

This cable works for me and has not blown any of my two helmets, but it might set your helmet on fire, get your children abducted by aliens and start wold war III, so be warned!

Diagram

At the helmet side is a 5-pin DIN connector and the PMR radio has an odd double-jack connector.
The drawing shows the cable-side of both plugs.

pin5-pin DIN connector
1 Speaker left
2 Speaker right
3 Speaker gnd
4 Mic (black)
5 Mic (white)
pinDouble-jack connector
1 Speaker left (shorted with 2)
2 Speaker right (shorted with 1)
3 Speaker gnd
4 Mic
5
6 Mic

Connections

5-pin DIN PMR Double-jack
1 1
2 2
3 3
4 4
5 6

Copyright © 2006 Martin Leopold Created on March 19, 2006
Last modification on March 19, 2006