I'm sure that someone will correct me if I am wrong but it is my understanding that the 210's USB connection is for a USB drive and Meridian have not allowed for it to be used as a class 2.0 audio input. (Unlike on the Explorer where the USB is an audio input)
Peter

Meridian 596 DVD for CD
Panasonic TV and BluRay
Meridian 565 Surround Proc (4.1)
Conrad Johnson Power Amp, Avalon Symbols (Front)
Rotel Power Amp and Neat Critiques (Rear)
REL Sub
Thinking about 218