| Write | Read | Size / bytes | Comment |
| SCSI command header | 6-10 | ||
| Transmission status | 8 | See table below | |
| SCSI command output data | >= 0 | Not used by all SCSI commands | |
| Transmission status | 8 | See table below | |
| SCSI command input data | >= 0 | Not used by all SCSI commands | |
| Transmission status | 8 | See table below |
| Code | Description |
| fb 00 00 00 00 00 00 00 | Transmission completed |
| f8 00 00 00 00 00 00 00 | Scanner expects a write |
| f9 00 00 00 00 00 00 00 | Scanner expects a read |