Audio Jack - 3.5mm TRRS (SMD)

This is a 3.5mm TRRS SMD audio jack. TRRS connectors are 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).