Adapter for Nextel headset?
 

Does anyone know of an adapter that will fit the headphone output on a Nextel phone? I'd like to use one for a talkback system with my business partner who mixes while I boom. With our set up, I boom, using a SoundDevices MM1 preamp, and she mixes on an SD302 mixer. I'd like to route the headphone output to the monitor input on the MM1.

I realize that Nextel phones are notorious for RF interference, but we would be using them in DirectTalk mode. On this latest generation of handsets, when you enter DirectTalk mode, the phone is essentially switched off of the cellphone network, and is apparently a regular walkie talkie. They still work when there is no cell reception whatsoever, and the phones are incapable of receiving or sending calls, alerts, texts, etc. The phone actually powers down for a second when you switch back and forth. It's quite neat.

Anyway, I'm contemplating buying a standard Nextel headset and seeing if it can be rewired. How hard would this be to do? The input on the MM1 is a quarter inch socket. A standard miniplug won't fit the Nextel input. It appears to be proprietary.