3.5mm is an output port, then how does “play/pause” button signal sent to phone?

Question

sorry i meant play pause button of connected earphones.

In: 8

Answer 1

3.5mm is the diameter of the hole, but not the number of contacts. Headphone output requires 3 wires TRS. A headphone with a microphone and volume controls requires 4 wires TRRS. The play/pause signal is a certain combination of signal on certain wires that the phone understands.