What does a 2012 Mac Mini need for microphone input?

I need a simply jack Mic unamplified physically connected to my Mac Mini (late 2012 model) through Audio-IN and it doesn't work.

I also tried the original iPhone's headphones to no avail and I wonder if this is normal?

Does the Mac Mini require a USB microphone or can I use the Audio Line-in port with another type of microphone?

UPDATE 10/14: I tried using a 3 channel splitter like this

then I plugged my speakers and my earphones with mic but nothing to do, mic still doesn't work... (maybe just because this splitter has a 3 channel male jack but it's a normal 2 ch; I bought it for 2€ from China so it's possible..)

Solution 1:

The audio-in port on Mac Minis is a line-level port, meaning that a standard PC microphone may not be audible without some sort of amplifier.

On any Mini from 2010 and later, you can use the Apple headset (the kind that comes with the iPhone), but you have to plug it into the headphone port, not the audio-in port. There are also adapters available that allow you to use any standard PC headset with that port.

On older Minis, you'll have to use a USB audio adapter. The iMic is a popular one, but there are many others out there.