The XLR 3-pin connector is the professional audio standard for balanced connections, providing excellent noise rejection over long cable runs through common-mode rejection. Pin 1 is always ground, pin 2 is hot (+), pin 3 is cold (-).
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | Shield / GND | Cable shield and chassis ground | GND |
| 2 | HOT (+) | Audio signal positive, non-inverting | ADC |
| 3 | COLD (-) | Audio signal negative, inverting | ADC |