SouceUSB records USB I/O requests and interface function calls in a binary log file and displays them in real-time. Separate records are created for initiation and completion. Requests and function calls can be logged from the time the system boots or logging can be easily started and stopped using keyboard shortcuts or menu commands.

For high throughput devices, SourceUSB can perform Background logging with progress bar.

Log View displays log entries as single line summaries. A Details Pane displays particulars for a selected log record: including URB fields, descriptors, setup packets, etc.

A Data Bar displays buffer contents for control, bulk, interrupt, and isochronous transfers. It also displays the raw byte stream for all descriptors.