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Serial port 1 switch settings, SW1
| COM | Switch 1 | Switch 2 | Switch 3 | Switch 4 |
| 1 | ON | OFF | OFF | OFF |
| 2 | OFF | ON | OFF | OFF |
| 3 | OFF | OFF | ON | OFF |
| 4 | OFF | OFF | OFF | ON |
| Disabled | OFF | OFF | OFF | OFF |
Serial port 2 switch settings, SW1
| COM | Switch 5 | Switch 6 | Switch 7 | Switch 8 |
| 1 | ON | OFF | OFF | OFF |
| 2 | OFF | ON | OFF | OFF |
| 3 | OFF | OFF | ON | OFF |
| 4 | OFF | OFF | OFF | ON |
| Disabled | OFF | OFF | OFF | OFF |
The COM I/O port addresses are fixed:
| COM Port | I/O address |
| 1 | 3F8 |
| 2 | 2F8 |
| 3 | 3E8 |
| 4 | 2E8 |
IRQ selection (SERCHINT jumper block: 4 columns, three rows)
An example is: R2C4 - R3C4 means Row 2 Column 4 connected to Row 3 Column 4
| IRQ | Serial port 1 | Serial port 2 |
| 2 | R2C4 - R3C4 | R1C4 - R2C4 |
| 3 | R2C1 - R3C1 | R1C1 - R2C1 |
| 4 | R2C2 - R3C2 | R1C2 - R2C2 |
| 5 | R2C3 - R3C3 | R1C3 - R2C3 |
To disable IRQs, do no install any jumpers
Parallel port I/O mode
The PIO mode jumper should be set to the leftmost two for printer mode, and the rightmost two for general I/O mode.
LPT assignment (LPTSEL, 2 columns, 3 rows)
| LPT | Port address | LPTSEL setting |
| 1 | 3BC | R3C1 - R3C2 |
| 2 | 378 | R1C1 - R1C2 |
| 3 | 278 | R2C1 - R2C2 |
| Disabled | - | No connections |
LPT interrupts (PTRINT)
IRQ5 is the leftmost two pins connected, IRQ7 is the rightmost two.
Real Time Clock (CLKINT)
| IRQ | CLKINT setting |
| 2 | R1C1 - R2C1 |
| 5 | R1C2 - R2C2 |
| 7 | R1C3 - R2C3 |
| Disabled | No connections |
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