The Master System uses a modified Atari 2600 pinout. No special components are needed.
| Pin | Function |
|---|---|
| 1 | Up |
| 2 | Down |
| 3 | Left |
| 4 | Right |
| 5 | +5v |
| 6 | Button I |
| 7 | TH |
| 8 | Ground |
| 9 | Button II |
Tiny numbers can be found on most DB9 connectors; they're small but they're there. Be careful not to wire things backwards!