What's the difference between X-SPDIF3 and X-SPDIF 2?

[Wei Cao]

The earth wires of IIS-LVDS output are isolated from the earth wires of USB connection.
Support 4 kinds of IIS-LVDS pin definitions.
Added an LED light to indicate if the external power supply is active.
Optimized CNC aluminum case improves electromagnetic shielding performance.