The kit version of the 4Cube has an USB interface and some manual control switches, but to try keep costs down and figuring they weren’t such a big draw for the average user we removed the hardware from the retail version. However all of the support is still built in to the software, and with a little work you can add those features back in to the retail version. This document explains how:
So what is that USB interface good for? This document explains everything you can do with controlling the 4Cube and 8Square:
