| # | R503 Pro Wire Color | Name | PIN # | Pin Name | Notes |
|---|---|---|---|---|---|
| 1 | Power | 3V3 | 3.3 Volts (Top Left Of Feather). | ||
| 2 | GND | GRD | Ground (Right Under 3.3 Pins). | ||
| 3 | TXD | 01 | TX on R503 <> RX on the Feather. | ||
| 4 | RXD | 00 | RX on R503 <> TX on the Feather. | ||
| 5 | Wakeup | 02 | Finger Detection (Pulled High). | ||
| 6 | Touch | 3V3 | 3.3 Volts (Top Left Of Feather). |
