Offering full USB v1.1 compliance, USB Chief Bus & Protocol Analyzers have 128 MB of recording memory, real-time event triggering and capture filtering, accurate time stamping, and extensive search and analysis capabilities. Rich graphical displays provide comprehensive illustration of raw bus signals, basic protocol packets, USB transactions, and higher level encapsulated protocols. The firmware, recording engine and operating software are field upgradeable using configuration files that can be downloaded from the firm's website. The display and analysis software is able to operate independent of the hardware, allowing it to function as a standalone trace viewer that can be freely distributed.