Interactive Connector Diagram
Click or tap any pin in the diagram below to inspect its signal assignment, electrical specification, and wire colour standard.
Supported Systems / Found On — Retro Machine Hubs
This connector is used on the following retro computer systems. Click any colour-coded badge below to open its full board-level repair, diagnostic, and schematic Machine Hub:
Connector Specifications
Full Pin Assignment & Wiring Reference
| Pin | Signal Name | Direction | Electrical Spec / Role | Wire Colour / SCART / Adapter Target |
|---|---|---|---|---|
| 1 | VDD (+5V DC) | Pwr | +5.0 V DC Supply (Present on Pocket/Color/SGB2 to power accessories; NC on early DMG) | NC in 2-player link cables (Do NOT short both +5V rails together!) |
| 2 | SO (Serial Output) | Out | 5V CMOS Serial Data Output (Crosses over to Pin 3 SI on the other Game Boy!) | Cross to Remote Pin 3 (SI) |
| 3 | SI (Serial Input) | In | 5V CMOS Serial Data Input (Crosses over to Pin 2 SO on the other Game Boy!) | Cross to Remote Pin 2 (SO) |
| 4 | SD (Serial Data / Mode) | I/O | Multi-player DMG-07 4-Player Adapter handshake line | Straight 4 -> 4 |
| 5 | SCK (Serial Clock) | I/O | 8.192 kHz (or 512 kHz CGB) Shift Clock (Output on Master, Input on Slave) | Straight 5 -> 5 |
| 6 | GND (0 V Ground) | GND | 0 V Common Signal Ground & Cable Shield | Straight 6 -> 6 (Black / Shield) |
Wiring a Custom Game Boy Link Cable or Arduino / USB Game Boy Printer Emulator
Every 8-bit Game Boy features a 6-pin External Expansion (EXT) port on the side of the shell driven by the Sharp LR35902 CPU's hardware synchronous serial shift register (`$FF01` SB Serial Transfer Data and `$FF02` SC Serial Transfer Control). During a link transfer, one Game Boy acts as the Master (driving the 8192 Hz internal clock on Pin 5 SCK, or 262/512 kHz fast clock on Game Boy Color) while the second Game Boy acts as Slave (using external clock). In a standard 2-player link cable, Pin 2 (Serial Out) and Pin 3 (Serial In) are crossed over between the two plugs.
- Never Tie Pin 1 (+5V VDD) Together Between Two Game Boys: In a 2-player link cable, leave Pin 1 disconnected at least on one end so two consoles' internal +5V DC-DC boost converters never fight each other! Pin 1 is only used to power unpowered accessories (like IR adapters or LED worm lights).
- Crossover Rule for Pokémon Trading & 2-Player Tetris: Connect Pin 2 (SO) on Plug A to Pin 3 (SI) on Plug B, Pin 3 (SI) on Plug A to Pin 2 (SO) on Plug B, Pin 5 (SCK) straight to Pin 5, and Pin 6 (GND) straight to Pin 6.
- Capturing Game Boy Camera Photos via Arduino: Because the Game Boy Printer speaks 5V SPI at 8192 Hz over Pins 2, 3, 5, and 6 (with a 10–15 kΩ pull-up resistor on Pin 3 SI), any 5V Arduino Uno/Nano running the open-source Arduino-GameBoy-Printer-Emulator sketch can dump your Game Boy Camera photos directly to a PC over USB!