| ZLP | Zero length packet. Used to terminate the current data transfer when the final packet is full and the total data length is less than the header specified | Section 5.5.3 USB 2.0 Bus Spec |
| CBW | Command block wrapper. Header that contains information about the data that is expected to be sent/received next | Section 5.1 USB Bulk Only Transport Spec |
| CSW | Command status wrapper. Status sent after data transfer to indicate success/failure and confirm length of data sent | Section 5.2 USB Bulk Only Transport Spec |
| Data Residue | Data residue (bytes) is the difference in the length requested in the CBW and the actual amount of data sent/received | Section 5.2 USB Bulk Only Transport Spec |