AFAIK the CT2-4400 requires at least Kernel 3.15+ and Xubuntu 14.04 comes with 3.13 - probably try with 16.04 or see if you can do a kernel upgrade on 14.04 to get a 3.5+ or 4.x kernel
Ah, here the details:
"Drivers are included in kernel 3.17 (for version 1) and 3.19 (for version 2). They can be built with media_build for older kernels [...]"