Parallel port connector
The parallel port connector is a 25-pin, D-SUB female connector.
| Pin | Signal | I/O | Description |
| 1 | /STROBE | O | Strobe |
| 2 | D0 | O | Data Bit 0 |
| 3 | D1 | O | Data Bit 1 |
| 4 | D2 | O | Data Bit 2 |
| 5 | D3 | O | Data Bit 3 |
| 6 | D4 | O | Data Bit 4 |
| 7 | D5 | O | Data Bit 5 |
| 8 | D6 | O | Data Bit 6 |
| 9 | D7 | O | Data Bit 7 |
| 10 | /ACK | I | Acknowledge |
| 11 | BUSY | I | Busy |
| 12 | PE | I | Paper End |
| 13 | SEL | I | Select |
| 14 | /AUTOFD | O | Autofeed |
| 15 | /ERROR | I | Error |
| 16 | /INIT | O | Initialize |
| 17 | /SELIN | O | Select In |
| 18 | GND | - | Ground |
| 19 | GND | - | Ground |
| 20 | GND | - | Ground |
| 21 | GND | - | Ground |
| 22 | GND | - | Ground |
| 23 | GND | - | Ground |
| 24 | GND | - | Ground |
| 25 | GND | - | Ground |