This is a TRRS (tip-ring-ring-sleeve) or 4-pin socket. Using a wireless jack (Bluetooth adapter) enables wireless audio and device ... On the other hand, 3.5 mm stereo (TRS) jacks have three contact ...

The goal with the S-balanced output is to reduce noise on TRRS headphones, though it supports both TRRS and TRS. Towards the center are your input and sample rate LED’s. Then you get the volume knob ...