What is the significance of a standalone unit? What does that mean
"Standalone" as referenced here means the unit will work without USB power. The original Edirol UA5 would only work if plugged into a USB connection. When you applied the Digi-Mod to this, it disabled the USB only feature allowing it to be used without the need for USB power (or "standalone").
I can not trace any reference on firewire 410 that it will work in stand alone mode. Check this before you purchase.
M-audio fast track pro works stand alone mode, but the spif will be 24bit/48khz in that case.
You should look into a DMod UA5. Its a great unit. If you find an Oade Modified UA5, you can get more modifications in the future. I used to use a Warm Mod Plus UA5 into a recorder (via Toslink). Worked great...
Terry