The 2.5mm TRRS connector is used as a balanced headphone output on portable audio players. Each channel has its own positive and return line with no shared ground.
| Pin | Name | Function | Type |
|---|---|---|---|
| T | Tip | Left channel positive | ADC |
| R1 | Ring 1 | Right channel positive | ADC |
| R2 | Ring 2 | Left channel negative return | ADC |
| S | Sleeve | Right channel negative return | ADC |