While the majority of USB devices have drivers written specifically for them by the manufacturer, Apple includes USB Class drivers with the Mac OS that will control the majority of these devices. This article describes class drivers.

Class drivers are software components that are able to communicate with many USB devices of a particular kind, such as disk drives, printers, or scanners. If the appropriate class driver is present, any compliant device can be plugged in and start working immediately without the need to install additional software. Mac OS 9 includes USB Mass Storage Support 2.0, a class driver that supports devices that meet the USB Mass Storage Class specification.

Because class drivers are written for generic classes of USB peripherals, some product specific features may not be available. If you find that some specific USB device function is not working, you may need to install the drivers included with the device, or download the most current version from the vendors Web site.