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 ).
3g