How to tap into trainer signal without inserting the plug on Tranis QX7?

[ninjazx11]

Hi all,
I want to tap into the trainer signal for head tracker.My head tracker uses 3 wires.Vin(upto 12v),Gnd and signal.Ideally i should be using one mono plug for signal and V+ and Gnd on different connector.But I would like to use just one 3 pin connector if possible.

I noticed on the trainer jack,inserting a plug breaks one connection but on the radio i couldn't find any kind of indication that radio displays that plug has been inserted.

Last time i tried to use stereo jack-plug but that was completely disaster.Everything got shorted.So Please suggest the best way to use a single 3 pin connector safely.Thanks.