The 3.5mm TRRS (Tip-Ring-Ring-Sleeve) connector with CTIA/AHJ wiring adds a microphone channel to a standard stereo headphone connector. Standard in all modern Android phones, laptops, and Apple devices after iPhone 6.
| Pin | Name | Function | Type |
|---|---|---|---|
| T | Tip | Left audio channel | ADC |
| R1 | Ring 1 | Right audio channel | ADC |
| R2 | Ring 2 | Ground / common | GND |
| S | Sleeve | Microphone input | ADC |