| Pin | Name | Direction | Color | Description |
| 1 | /STROBE | Out | | A low on this line indicates, that there is valid data at the host. When this pin is de-asserted, the +ve clock edge should be used to shift the data into the device. |
| 2 | Data 0 | IN/OUT | | Address, Data or RLE Data Bit 0 |
| 3 | Data 1 | IN/OUT | | Address, Data or RLE Data Bit 1 |
| 4 | Data 2 | IN/OUT | | Address, Data or RLE Data Bit 2 |
| 5 | Data 3 | IN/OUT | | Address, Data or RLE Data Bit 3 |
| 6 | Data 4 | IN/OUT | | Address, Data or RLE Data Bit 4 |
| 7 | Data 5 | IN/OUT | | Address, Data or RLE Data Bit 5 |
| 8 | Data 6 | IN/OUT | | Address, Data or RLE Data Bit 6 |
| 9 | Data 7 | IN/OUT | | Address, Data or RLE Data Bit 7 |
| 10 | Ack | In | | A low on this line indicates, that there is valid data at the Device. When this pin is de-asserted, the +ve clock edge should be used to shift the data into the Host. |
| 11 | Busy | In | | When in reverse direction a HIGH indicates Data, while a LOW indicates a Command Cycle. |
| 12 | Paper Out / End | In | | When Low, Device acknowledges Reverse Request. |
| 13 | Select | In | | Extensibility Flag |
| 14 | Auto Linefeed | Out | | When in forward direction a HIGH indicates Data, while a LOW indicates a Command Cycle. |
| 15 | Error / Fault | In | | A LOW set by the device indicates reverse data is available |
| 16 | Initialize | Out | | A LOW indicates data is in reverse direction |
| 17 | Select Printer | Out | | A HIGH indicates Host is in 1284 Transfer Mode. Taken low to terminate. |
| 18 | GND | In | | Signal Ground |
| 19 | GND | | | Signal Ground |
| 20 | GND | | | Signal Ground |
| 21 | GND | | | Signal Ground |
| 22 | GND | | | Signal Ground |
| 23 | GND | | | Signal Ground |
| 24 | GND | | | Signal Ground |
| 25 | GND | | | Signal Ground |