Hardware Reference
In-Depth Information
mouse, it works only on the single interface for which it was designed. Most of the time,
you find the designation for which type of mouse you have printed on its underside. If
the mouse didn't come with an adapter or come bundled with a system, it probably won't
work with an adapter.
USB
TheextremelyflexibleUSBporthasbecomethemostpopularporttouseformiceaswell
askeyboardsandotherI/Odevices.Comparedtotheotherinterfaces,USBmice(andoth-
er USB pointing devices such as trackballs) have the following advantages:
• USB mice move much more smoothly than the traditional PS/2 type. This is because
the frequency with which the mouse reports its position is much higher. A typical
PS/2mousehasareportingrateofabout40Hz,whereasanaverageUSB-wiredmouse
has a reporting rate of 125Hz (most USB wireless mice have a reporting rate of
40Hz-50Hz). Several utilities are available to test and adjust the mouse frequency.
• USB mice and pointing devices, similar to all other USB devices, are hot-swappable.
If you like to use a trackball and your computing partners prefer mice, you can just
lean over and unplug the other users' pointing device and plug in your own, or move
it from PC to PC. You can't do that with the other port types.
• Multiple pointing devices. With USB, you can easily have multiple pointing devices
connectedsimultaneously,andyoucaneasilyswitchbetweenthemorusethemincol-
laboration.
• USB mice can be attached to a USB hub. Using a hub makes attaching and removing
your mouse easy without crawling around on the floor to reach the back of the com-
puter. Many computers have front-mounted USB ports, letting you easily attach and
remove a USB mouse without the use of an external hub.
Although the early USB mice were decidedly on the premium end of the price scale, low-
cost USB mice are now available for as little as $10. That said, plenty of optical and laser
mice are available with premium prices up to $100 and more.
If you want to use a USB mouse at an MS-DOS prompt, in Windows Safe mode, or in
some other environment outside of normal Windows 98 or later, make sure that USB
Legacy mode is enabled in your PC's BIOS, as discussed earlier in this chapter. Legacy
mode enables non-USB-aware systems to recognize a USB keyboard and mouse.
Afourthtypeofconnection,thebusmouse(referredtobyMicrosoftastheInPortmouse),
used a dedicated ISA bus adapter card and is considered long obsolete.
