| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | CGND | Chassis ground | |
| 2 | +5V | → | +5 VDC |
| 3 | CGND | Chassis ground | |
| 4 | X2 | ← | Horizontal movement line (connected to VIA PB4 line) |
| 5 | X1 | ← | Horizontal movement line (connected to SCC DCDA-line) |
| 6 | n/c | Not connected | |
| 7 | SW- | ← | Mouse button line (connected to VIA PB3) |
| 8 | Y2 | ← | Vertical movement line (connected to VIA PB5 line) |
| 9 | Y1 | ← | Vertical movement line (connected to SCC DCDB-line) |