OMP-Peltor Adapter
The following is something I drafted the last time someone asked this question. However, AFAIK, there is no way to know if it ever worked (the guy I sent this to never responded).
Nonetheless, the usual disclaimers apply and please don't come crying to me if you fry your headset or intercom...
Bill W.
This really is no more difficult than setting up a home stereo system, with only a slight chance for some needed guesswork.
In my experience the OMP and Terraphone systems are compatible, and I've never managed to fry any of the mics or earphones while doing this. However, since you have the Peltor type I must point out that you're in uncharted territory from my experience and all the usual disclaimers apply.
Nonetheless, basic logic would dictate that by using a Peltor-Terraphone adapter you will be bringing the system into compatability with an OMP intercom, since I've already shown that OMP/Terraphone systems work together with nothing more than a few home stereo wires.
So, assuming you have a Peltor head set and that the in-car intercom unit is an OMP type, you will (of course) need the Peltor-Terraphone adapter, while the rest of the wiring and adpaters can be found at any Radio Shack or Walmart store.
Flow Chart
----------
Peltor headset-> Terraphone adpater-> wiring/connectors-> OMP amp
So, it's the 'wiring/connectors' bit that needs to be sorted out...
Since the Peltor headset plugs into the Terraphone adapter, the Terraphone adapter must end in 1/4" stereo male plug (I've actually never seen one, but this MUST be the case based on the Terraphone systems I've seen).
This is what you wiil need to convert to an OMP 5-pin DIN:
(a) 1/4" _female_ stereo to 2-wire RCA connectors
(b) 5-pin DIN _female_ plug to 4-wire RCA connectors
The only slighty tricky bit is dependent on the type of RCA connectors items (a) and (b) have. You may find that you can only get (a) and (b) with male RCA plugs, so you'd then also need two lengths of standard RCA female-to-female wiring to match them up.
The beauty of this is that the parts are all readily available and you can build this harness for <$10 US.
Now that you've got everything, you may notice that there are two extra RCA plugs from the 5-pin DIN plug. This is where the trial and error method may need to take over. Try my suggested colour matching below and if it doesn't work you will need to sit in the car with the driver plugged in and the intercom turned on to work out how to map the wires.
On my harness, the red RCA connector from the DIN plug is matched to the red RCA connector from the 1/4" stereo plug.
Then, the grey RCA connector from the DIN plug is matched to the white RCA connector from the 1/4" stereo plug.
This leaves both the white and black RCA connector from the DIN plug as unused.
Give it a shot and, if it doesn't work, at worst you've spent $10 on a bunch of home stereo wires you may never need.