Radio Frequency (RF) is the preferred medium to support wireless keyboard devices and any other wireless PC peripheral used for sessions of relatively long duration or conducted at a relatively long range. In contrast, IR is the preferred medium to support devices used in point-and-shoot, ad-hoc sessions of short duration, conducted at short range.
Use of RF in cordless peripherals such as keyboards, mice, joysticks, and remote controls is attractive to users. These cordless peripherals are direct substitutes for the devices attached to the PC with cables.
Other uses of RF attractive to users are home and small-office networking, cordless telephones, and cordless audio headphones. Manufacturers are encouraged to develop low-priced, relatively short-range solutions for these markets.
Manufacturers who are implementing designs that include RF devices are strongly encouraged to communicate with Microsoft. Microsoft wants to work with manufacturers to standardize RF protocols and media within the computer industry. Please send e-mail to ihv@microsoft.com. For more information about RF alternatives, see http://www.microsoft.com/hwdev/devdes/.
34. Select a low-power RF alternative
| Recommended |
For relatively short-range RF devices, it is possible to use a low-power RF device. Use an RF device appropriate to the application. For example, cordless keyboard and trackball devices only need a maximum range of 15 to 20 feet.
35. Consider noise and conflict with other RF devices in the environment
| Recommended |
RF devices should have a way to defeat noise, such as EMI interference. Also, programmable channel selection, carrier sensing, or the relatively expensive spread-spectrum or frequency hopping techniques can be used to share the RF medium with other RF devices that might be in the environment.
36. Separate certification of the system and the RF device
| Recommended |
Rules for certifying low-power, short-range, unlicensed RF devices vary greatly from country to country. By configuring the RF device as a system add-on, local certification of the system will not be blocked while waiting for certification of the RF device, which might take longer. Configuring the RF device as a system add-on also enables adding RF support to legacy hardware.