Active (real time) noise reduction.
|David Edwards Derelict Ship.|
I'm kinda fascinated by analog audio over Cat 5 (and 6, 7, 8, etc.) 4 channels is the most you can expect because there are 8 wires inside. Also, you want the shielded stuff so the higher-end cable is better. You can go hog-wild with digital audio on (say) Cat 8, but this is just cheap 4-channels of analog (and it's bi-directional.)