The power key was replaced with a more conventional power button on early USB keyboards, thanks to a proprietary pin wired to the Macintosh's power supply in Apple's early USB implementations, subsequently eliminated on the Pro Keyboard along with the special power supply pin. On keyboards with function keys, it was placed either on the left or right edge of the same keyboard row as the function keys on keyboards without function keys it was placed in a central location above the other keys. On Apple Desktop Bus keyboards, a power key ( ◁), used to turn on computers that supported it (and to type the Mac three-finger salute).On the newest aluminum keyboard, these functions are accessed with the function keys, just like on the Apple laptops.
Apple, since the release of the Pro Keyboard, provides these last four keys on desktop keyboards above the numeric keypad where status indicator lights are on many IBM PC keyboards. Notebook computers typically include additional assignments shared with function keys – reduce and increase brightness, volume up, volume down, mute, and eject ( ⏏).A Help key, instead of an Insert key, or on the most recent aluminum keyboards, a fn key, which toggles the function of the function keys between their default functions and special functions (volume control, Exposé, etc.).An "equals" key ( =) added to the numeric keypad.In Unicode, the Clear key is represented by U+2327 ⌧ X IN A RECTANGLE BOX, defined as "clear key".
A Clear key, instead of a Num Lock key, on models with full numeric keypads, as these are dedicated to numeric input and not generally used for cursor control.
Compact keyboards such as the bluetooth wireless aluminium keyboard and the built-in keyboards on all Intel-based Macintosh notebooks range from F1-F12 only, just like IBM PC keyboards. F17-F19 keys were introduced with the aluminium USB keyboard.
Compared to their equivalents on the standard IBM PC keyboard layout the Command key and the Option key are located in reverse order. It functions as the Alt key in Unix and Windows environments. It serves the function of the solid-Apple key in Apple II applications. Like the Shift and Control keys, the Option key serves as a modifier for the Command key shortcuts, as well as being used to type many special characters.