Realtek Audio Manager Line In (Apple Headphones)

Good point, Duzzy. A PC mic jack is looking for the Mic signal on the Tip and provides 5VDC on the Ring (plus ground). If the mic signal and voltage are not on those then you are correct that an adapter is needed.

@Duzzy, it's exactly like that one in the picture. Once I purchase a splitter, do I choose the line-in option?

With a splitter/adaptor you should get 2 plugs one for the headphones that you would plug into the line out/speakers port and I would plug the second one for the mic into a mic port so you can take advantage of the mic boost functions and any other mic settings. Plug one in at a time then choose the appropriate option in the Realtek Manager for each.

I believe the line in port is generally used for devices that have a higher output than the mic port can support.

You can't just get any kind of splitter either. You can find splitters that will split your standard 2 channel into two plugs, just doubling your outputs and possibly a splitter that splits 2 channel into two 1 channel plugs, a plug for the left channel and a plug for the right channel.

What you need is something like this - Amazon.com: Headset Buddy Adapter, it doesn't state anything about 3 channel but the details/description pretty much tells you it'll work. It's colour coded too which helps.

The Line In port is a stereo (two channel) input. The Mic input is a mono input. They both work on the same audio signal levels (basically near "line level"). A standard "PC mic" is a condenser type mic and requires 5VDC to operate, thus the mic input jack has the signal on the "tip", 5VDC on the "Ring" and the third connection is ground.

Some Laptop PC's have a combination Mic/Line In jack and it senses what is plugged in (mic or stereo input).

@Fireberd
I should have known that considering your've already mentioned that in previous posts so thanks for clearing that up.

So the OP should try selecting Mic in the Realtek Manager and if that doesn't work then the line in should, could, maybe, it is a computer (AKA Stress Machine) after all?