What is 3.5mm jack?

A 3.5mm jack, also known as a headphone jack, is a standard audio connector used in most portable electronic devices such as smartphones, laptops, and MP3 players. It is a small, round plug that can be easily plugged and unplugged from a device. The jack typically has three metal bands, which enable stereo audio transmission and microphone input simultaneously. The three major types of 3.5mm jacks are TS (tip sleeve), TRS (tip-ring-sleeve), and TRRS (tip-ring-ring-sleeve). TS jacks transmit mono audio, TRS jacks transmit stereo audio, and TRRS jacks transmit audio and microphone inputs or remote controls. Nowadays, some devices do not include a 3.5mm jack, opting for other audio connectors such as USB-C or Lightning.