The EQDir USB cable is designed for EQ3, EQ5, HEQ5, and EQ8 mounts. It enables control of your mount from PC, Mac, or StellarMate. Simply connect the RJ45 plug to the handset port on the mount and then connect it to your device via USB. You can use any planetarium program (e.g. KStars) to control the mount to slew to any object.