| Pin | Signal | Description |
| 6 | GND | to PC USB pin 4 |
| 9 | USB +5V | to PC USB pin 1 |
| 10 | USB D+ | to PC USB pin 2 |
| 15 | USB D- | to PC USB pin 3 |
| 16 | Rx | serial |
| 17 | Tx | serial |
Pins 3, 4 should be shorted and connected via 1N4148 diode to +5V supply, pins 6 and 12 shorted (GND) in serial cable.
Pins 6 and 13 (GND) should be shorted in USB data cable.

