how does the headphone mic/button work?

[dishwashersafe]

anyone? posted this in hacks with no response...don't make me have to cut up my headphones : (

What I'm trying to do is integrate my phone with my car using only the jack. I'd be wiring up an unused steering wheel button and the car's mic but I'm not sure how to connect it to the 4-pole jack. Anyone know? I don't want to destroy my headphones to see how it's wired. Thanks!

 

[ulbador]

anyone? posted this in hacks with no response...don't make me have to cut up my headphones : (

What I'm trying to do is integrate my phone with my car using only the jack. I'd be wiring up an unused steering wheel button and the car's mic but I'm not sure how to connect it to the 4-pole jack. Anyone know? I don't want to destroy my headphones to see how it's wired. Thanks!

From the top:
Tip Left audio
Ring Right audio
Ring Common/Ground
Sleeve Microphone

I'm not sure about ones with an inline button. Is there an Apple product that has a PTT (push to talk) button? Otherwise the basic way this would work is it would just disconnect and connect the MIC line when the button is pressed. I doubt the iPhone has the necessary internal hardware to detect a button press. When the MIC is "on" in whatever program, it's just on


EDIT:

After some more research, pushing that button shorts the MIC line to Ground

 

[dishwashersafe]

From the top:
Tip Left audio
Ring Right audio
Ring Common/Ground
Sleeve Microphone

EDIT:

After some more research, pushing that button shorts the MIC line to Ground

Thanks for the quick reply! That was my suspicion but it's good to see it confirmed.