USBExplorer 3.3 could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. This program is a product of Ellisys.
The following versions: 3.3 and 1.0 are the most frequently downloaded ones by the program users. The program's installer is commonly called USBExplorer.exe. The program is included in System Utilities. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software.
From the developer:
The USB Explorer 200 is a non-intrusive high speed USB 2.0 protocol analyzer that enables you to display bus states, packets sent and decode descriptors of the USB protocol. It can detect errors in devices, host controllers, embedded softwares or drivers as well as measure their performance. Very simple to use, this USB analyzer is the ideal companion for anyone developing USB devices, hosts, embedded software or drivers.
You may want to check out more software, such as Ellisys USB Explorer 280 Generator, which might be related to USBExplorer.