system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: Why computers use separate jack for mic and headphones while mobiles use the same jack for input and output.?
gpt
Typically those combined jacks have the same number of contacts as the separate jacks put together. They are just all together.

You can buy adapters that split these up or merge them to  connect devices meant for one type to the jack meant for the other.

Small devices tend to use combined jack because it saves space and because people are less likely to use separate peripherals for audio in and out on something small like a phone or tablet.

Computer use separate jack because you are more likely to have separate headphones and microphones on your desk and because they have room to spare.