The X-keys USB GPIO unit features 10 configurable ports which can be 5 volt outputs, short-to-ground inputs, or 5 volt pull down inputs. It also has two more dedicated 5 volt outputs, and four more dedicated short-to-ground inputs. Free Programming Software: Windows: MacroWorks 3.1. The ten configurable ports are set with a free Windows utility we provide via download (link). All inputs and are programmable and can send a wide range of USB keyboard, mouse, game controller, multi-media and other proprietary USB HID messages. All outputs can be triggered via USB HID with support from our free SDKs for Windows, OS X, Linux, and Android. A standard HD15 male connector provides reliable connection to all configurable I/O ports and dedicated outputs. Two 3.5 mm TRS (Tip-Ring-Sleeve, AKA Stereo) ports provide connection to the four dedicated short-to-ground inputs to facilitate the addition of external switches.