So I know Cat5 is 4 twisted pair non-shielded and works fine for ethernet and is used quite a bit in pro audio setups. In many of the churches I work at, I notice they use digital stage boxes to convert analog mic and line signals to digital ethernet (like?) and send it via cat5 to the FOH console. They also use the cat5 to send individual signals back to mini/personal stage mixers www.youtube.com/watch?time_continue=7&v=wm4Et-qtVpY&feature=emb_logo for IEM or headphone monitoring.
For analog audio, I'm pretty sure using cat5 without shielding would pick up hum and have crosstalk between channels but who know what they'll come up with next?
I looked and the site and it was not clear to me exactly what cranborne is doing with their electronics but I'd have to bet it's a digital signal they are sending via cat5. If not and they are actually sending analog audio, I'd love to know how.
OK, I dug around the site a little more and YES it is analog, sorry for doubting you Hex, my bad . BUT, they do mention using "Shielded Cat5". So that should work fine and the circuitry should be basically the same as any balanced driver/receiver system.