6.2 MS IntelliMouse Explorer (PS/2, USB)

This mouse has a wheel which also acts as the button 2 (middle button).
There are two side buttons; they are recognized as the buttons 4 and 5. The wheel movement is recognized as the Z axis motion.

To use this mouse as the PS/2 device and the OS supports PS/2 mouse initialization:

Option "Protocol" "ExplorerPS/2"

To use this mouse as the PS/2 device but the OS does not support PS/2 mouse initialization (the wheel and the side buttons won't work in this case):

Option "Protocol" "PS/2"

To use this mouse as the PS/2 device and the OS supports automatic PS/2 mouse detection:

Option "Protocol" "Auto"

To use this mouse as the USB device and the OS supports the generic HID protocol:

Option "Protocol" "usb"

To use this mouse as the USB device and the OS supports automatic mouse detection:

Option "Protocol" "Auto"
--
Excerpt from X 4.2.1
/usr/X11R6/lib/X11/doc/README.mouse