Jack plug sizes, typically ranging from 2.5mm to 6.35mm, correspond to the socket size in your audio device. The size needs to match for a proper connection, with 3.5mm being common for headphones and smaller audio equipment.

The rings on a jack plug, known as insulating bands, denote the number of separate channels the plug can carry. One ring means mono sound, two rings for stereo, and three for stereo with a microphone channel.

Compatibility depends on the jack plug type and the audio device. It's essential to match the plug size and configuration (TS, TRS, TRRS) with your device's requirements for proper audio transmission.

Common types of jack plugs include TS (Tip-Sleeve), TRS (Tip-Ring-Sleeve), and TRRS (Tip-Ring-Ring-Sleeve), each supporting different audio functions like mono, stereo, or microphone input.

Colours on jack plugs and sockets often indicate their function. For instance, green typically denotes a headphone output, while pink indicates a microphone input, helping to guide the user for correct connections.

Jack plug connections work by inserting the plug into a corresponding audio jack, creating an electrical circuit that transfers audio signals. The number of conductive areas separated by insulating rings on the plug determines its function.