The Motion Computing J3400/J3500 Tablet PC Buttons Windows Driver refers to the software that enables the functioning of the customizable hardware buttons (such as function buttons, volume control, or tablet-specific features) on the Motion Computing J3400 and J3500 tablet PCs. These tablets are equipped with specialized physical buttons that can perform various functions, and the driver is necessary to allow the operating system (usually Windows) to recognize and interact with these buttons.