| Pin | Name | Description |
|---|---|---|
| 1 | D0 | Data 0 |
| 2 | D1 | Data 1 |
| 3 | D2 | Data 2 |
| 4 | D3 | Data 3 |
| 5 | D4 | Data 4 |
| 6 | D5 | Data 5 |
| 7 | D6 | Data 6 |
| 8 | D7 | Data 7 |
| 9 | /CS | Chip Select |
| 10 | IRQ | Interrupt Request |
| 11 | GND | Ground |
| 12 | /RST | Reset |
| 13 | GND | Ground |
| 14 | ACK | Acknowledge |
| 15 | GND | Ground |
| 16 | A1 | Address bit |
| 17 | GND | Ground |
| 18 | R/W | Read/Write |
| 19 | REQ | Data Request |
The Atari uses this port to connect external Hard Disk following a specification call ASCI close to SCSI with a DB19M-DB19M cable. Connections in cable are straight 1-1 to 19-19 wires (not sure).
