OnStep is a computerized goto system, usually for stepper motor equipped mounts though any step/dir interface motor driver (including servo) should work. It was designed, from the beginning, as a general purpose system and provisions were made in the firmware to allow for use on a variety of mounts including Equatorial and Alt/Az (GEM, Fork, Dobsonian, etc.) It uses an LX200 like computer command set with a few extensions to suit hand controller-less operation.
There's a telescope hand controller App for Android (free in the Google Play Store,) an option to control through a website (Smart Web Server,) and a dedicated physical hand controller (Smart Hand Controller.) Or, on a PC there's ASCOM and INDI drivers for control. These options allow you to setup and control OnStep using a wide range of software including my Sky Planetarium, Cartes du Ciel, Stellarium, SkySafari, KStars, PHD2, etc. You can see most of the control possibilities in the diagram below: