Targa Miata
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July 30, 2011 - I've been waiting for this for a while.
It's a cable that will let me plug an iPod or iPhone into the Peltor FMT120 intercom. This cable isn't available in North America, despite the fact that all the resellers of the FMT120 use the same product description that includes this feature. This says something about the size of the Peltor rally intercom market in North America, I suspect. I had to bring this cable in from Demon Tweaks in the UK, which wasn't cheap.
Still, it'll let Janel and I make phone calls using the intercom as well as listen to music on long transits. If you look at the cable as a stereo system, it was a pretty good deal! Less than an iPod interface for our BMW, for example.
Since this thing can't be obtained at reasonable cost in North America, I'm going to reverse-engineer it so anyone can duplicate it - just as I did with the transit headsets a while back.
I've identified the plug that goes into the intercom as a 5-pin mini XLR, aka a Switchcraft TA5FL. Prices vary online, but Rugged Radios has them for under $6. The other end of the cable is the usual 1/8" 4-pole iPhone/iPod connector. The easy way to start would be with an iPhone cable for something else such as a $12 "microphone extension cable" and just replace the plug at the other end. You could also hook up another kind of phone if you know the wiring of the phone connection.
The Apple end works as such: the tip is the left audio out. The first ring is the right audio out, the second ring is the common/ground and the base ring is the microphone. On the Peltor end, the pins are numbered 1-5.
Pin 1: ground (second ring on Apple plug)
Pin 2: ground (second ring on Apple plug)
Pin 3: audio from phone (tip and first ring on Apple plug)
Pin 4: microphone (base on Apple plug)
Pin 5: microphone (base on Apple plug)
Happy soldering!
tags: peltor, intercom