Wireless Input Devices

For several years , many manufacturers have offered cordless versions of mice and keyboards. In most cases, these devices have used either infrared or short-range radio transceivers to attach to standard USB or PS/2 ports, with matching transceivers located in the mouse or keyboard. Wireless input devices can be especially useful for projector-based presentations, allowing the operator to sit far away from both the projector and the laptop system. They can also be used in cramped home-office environments or where a large-screen TV/monitor device is used for home entertainment and computing. Some game controllers are now available in wireless forms as well.

Radio Versus Infrared

Although some vendors still use infrared transceivers, most vendors support radio signals. Having used both kinds, I can tell you that a radio-frequency input device beats an infrared input device hands down for use at home or in a small one- or two-person office. Infrared requires an unobstructed direct line between the transceivers. When I used an infrared keyboard/pointing stick combination at a client site, I was constantly re-aiming the keyboard at the receiver to avoid losing my signal. When I used a radio mouse, on the other hand, I didn't have to worry about line-of-sight issues. The only advantage to infrared is cost, but the problems of reliability in my mind outweigh any cost savings.

Major Vendors and Products

Unlike conventional mouse and keyboard producers , whose numbers are legion, the ranks of cordless input device makers are small. The major vendors include the following:

• Logitech makes radio-frequency mice and keyboards.

• Microsoft makes radio-frequency mice.

• Other vendors make infrared mice and keyboards (usually combination units).

Logitech

Mouse maker Logitech manufactures both radio-frequency wireless keyboards and radio-frequency wireless mice (first developed in 1992). Because Logitech developed wireless mice for several years before developing wireless keyboards, its older wireless mouse receivers work only with mice; you must use a separate receiver for its wireless keyboards. If you want to use a wireless mouse and keyboard, you should purchase both units as a bundle; a single receiver with dual mouse and keyboard channels is usually supplied with bundled wireless keyboard/mouse sets. Check Logitech's support Web site for details about the compatibility of a particular receiver with a specified Logitech wireless mouse or keyboard.

Logitech's cordless series of wireless keyboard/mouse combinations can be attached through either the PS/2 mouse/keyboard ports or the USB port, allowing them to be used with older, non-USB-aware versions of Windows as well as the newer versions (Windows 98 and later) that support USB. Older wireless mice use either the PS/2 port or the serial port.

Microsoft and Other Vendors

Microsoft makes a series of wireless input devices as of this writing ”those using proprietary RF technology as well as industry-standard Bluetooth technology. The receivers attach to either a PS/2 mouse port or USB port; however, some are PS/2 only or USB only. The Bluetooth models should be able to interface to any laptop with built-in Bluetooth capability, without having to use the receiver included with the mouse.

Older infrared input devices normally combine both keyboard and mouse functions. These devices are offered by vendors such as Acer, PC Concepts, SIIG, and others, and they normally attach to the PS/2 mouse and keyboard ports. For improved reliability, some feature dual infrared transceivers in the keyboard or receiving unit to enable the unit to be moved around without losing the signal. Some infrared models were designed with a long signal range for use in computer presentations, but most of these have since been redesigned to use radio-frequency technology.

Wireless Pointing Device Issues

Before you invest in wireless pointing devices for multiple computers, you should be aware of the following issues:

• Line-of-site issues ” Infrared devices won't work if the IR beam between the pointing device and the receiver attached to the system is blocked. These units are not as suitable for casual in-the-lap use as radio-frequency units would be.

• Radio-frequency interference ” Although early wireless mice used analog tuners that were hard to synchronize, today's wireless input devices normally use digital selectors. However, if several similar devices are used in close quarters , a receiver might actually receive data from the wrong mouse or keyboard. Also, metal desks and furniture can reduce range and cause erratic cursor movement. Most wireless devices operate around 27MHz, thus minimizing interference from devices such as cordless phones. Bluetooth devices use the 2.4GHz band , which is the same as 802.11b Wi-Fi as well as many newer cordless phones, meaning they can interfere if used simultaneously . Check with the vendor of your specific wireless device for tips on overcoming interference issues.

• Battery life and availability ” Early wireless devices sometimes used unusual, expensive batteries. Today's units run on common battery types, such as AAA. Battery life is usually rated at about 6 months. Make sure you have spare batteries for the input device to avoid failures due to running out of battery power. The included software by companies such as Logitech gives users an onscreen warning when batteries run low. Some now include rechargable batteries, which can save money in the long run. To save battery life when using an optical wireless mouse, try working on brighter or whiter surfaces. Many optical mice adjust their sensors based on the illumination of the surface; this is why you may see the light in the mouse change intensity. The less intensely the internal LED operates, the less battery power is being used.

• Location ” The range of wireless can vary from 6 feet to as many as 30 feet. Consider where the device will be used before making your purchase. For instance, in an office where multiple devices may be used at the same time, a close-range device may be more desirable in order to avoid "crosstalk" among devices. On the other hand, the home user who wants to sit away from the screen while maintaining control may desire an extended range.

• User experience ” Different users will have different expectations of wireless input devices, but in general, the more a wireless input device acts like its wired siblings, the better. The fact that a device is wireless should not compromise its functionality. If reliability, connection, and driver problems hinder proper usage, the device isn't worth using. Hardcore gamers who need the fastest response time possible will generally favor the responsiveness of a wired optical mouse over any wireless mouse. Although minimal, some lag time does exist. Some mice can require up to 0.25 centimeters of movement before responding. This lag time may also affect users doing graphical work, which requires the superior consistency and accuracy of a wired optical mouse.