Polar T34 Receiver Tinkering

I bought a Kettler hometrainer which has an integrated receiver for a Polar T34 Heart Rate monitor (sold as 'Kettler Cardio Pulse Set). The extension kit of the Kettler bike comes with a Polar Receiver module (with 94035939.02 2213 written on the back. So since my hometrainer has an integrated wearlink receiver I actually don't need the spare receiver module that came with the Polar T34, so I was thinking of hooking it up to my pc, and having my pc gather my heartrate in a more advanced way than my hometrainer can do.

For now I was looking around on the web and found that Adafruit and Sparkfun have similar modules (note to self, I'm not sure if T34 and T31 for example are compatible, T31 is always mentioned with a rmcm01 receiver, at this point I would guess T34 is more an OEM-like version, while T31 is more something you can get directly from Polar).

Well in any case, I have a T34 at my disposal, and a OEM-like receiver I got with it. The output of this receiver looks like an audio jack which has actually three signals, and just thinking that these three signals might be Vcc, a beat pulse and GND seems a reasonable guess. So I created the following setup which successfully makes a LED flash whenever my heart beats:

Which basically connects 5V and GND from my Arduino Uno to a breadboard and uses this to feed the receiver. Next the beat signal (central connection) is wired via a LED and a resistor back to GND on the breadboard. The GND connection on the audio jack is actually the same GND connector as when using it for regular stereo audio. As annotated on the following image:

Some other pictures of the receiver module: