LDTR-WG0078 3.5mm Audio Socket Stereo Sound Module with Mic for MP3 Player

1. The audio-style connectors that you see on some phones, MP3 players and development boards. TRRS stands for "Tip, Ring, Ring, Sleeve," which reflects the fact that, unlike a standard stereo connector, this actually has three conductors and a ground. Some devices use the extra conductor for a microphone ( like hands-free headsets ) or to carry a video signal ( like in some MP3 / MP4 players ).