The CPRO-11SI allows an external audio signal to be inserted into your HDMI or DVI (with an HDMI to DVI adaptor) signal path. The unit allows you to insert analogue stereo or multichannel surround sound (via the digital optical input) giving you the flexibility to add your choice of audio to the video while extending your HDMI signal. It also has the added benefit of 4K2K and 3D support, allowing full resolution video and eliminating the need to downscale the image. Supports 4K2K resolution and 3D signals. Compliant with HDMI, HDCP 1.2.