I bought a headset, and it has a (obviously) male headphone input and microphone output. Problem is, MacBook Pros don't have a microphone input. Instead, they have an audio line in.
However, relatively recent MacBook Pros apparently combine the audio out with a microphone input, allowing, for instance, iPhone headsets to be plugged in the computer and work as expected.
So I was wondering if there were adapters that took the two jacks and merged them into a single, "iPhone-compatible" jack, that I could plug in the MacBook Pro.
Best Answer
Of course the combined jack on Macbook is analog, of course it accepts mic signals (works with apple and other brand headsets for iPhone, for example) and not just line in signals (you can even plug electric guitar with passive adaptor from iRig) and as Zneak properly points in his question, it would not be too difficult to make an adaptor that splits one headset jack on Macbooks into headphone and mic, which is also great if you want to use some top notch headset like Sennheiser PC 360. Unfortunately I was not able to find such a product, only a guide on how to make one.
Last but not least, USB headsets are in no way better. They only use extra CPU power, clutter USB ports and are only as good as the DACs, ADCs, headphone and mic they employ. Now these components are much better inside Macbook and good analogue headset...
The Headset Buddy at Amazon claims to do just this. But I am not sure how well it will work, as the headset pinout Apple uses in Macbook, iPhone or iPad is different from some other manufacturers (that is why you cannot use iPhone headset with, say Samsung Galaxy S)