[TexasGator]

“Mic/In. Well, hooey bluey, this means there’s no stereo line input..”

TRRS = Ground-Left-Right-Micrphone

[Paul R.]

Depends on application / equipment — SFAIK, laptops’ TRRS jacks are generally as I mentioned.

https://www.youtube.com/watch?v=6vCu5NvmnNc

1:54

and,

https://en.wikipedia.org/wiki/Phone_connector_(audio)

(TRRS Standards section)