This section summarizes the basic design features for wireless components, provided either as IR or RF adapters. IR solutions are based on communication standards developed by the Infrared Data Association (IrDA). IR solutions are further differentiated as IrDA and Control IR based on the following features:
No standard exists for legacy consumer IR, which is in wide use today to control consumer-electronics devices such as televisions, VCRs, CD players, and so on. PC systems designed to control such devices or to be controlled by existing IR remote controls must accommodate the lack of standards by adopting a universal consumer-IR approach. Therefore, no PC 98 protocol recommendations are made for interoperability with legacy consumer-IR devices. Because some IR transceiver manufacturers add support for consumer IR in their IrDA transceivers, PC 98 requirements are specified for using such multiprotocol IR devices in a PC.
Many manufacturers are implementing integrated IR solutions for mobile PCs. Various form-factor and environmental issues have limited the adoption of wireless solutions for desktop PCs, including receiver placement in the office environment and limiting conflicting device signals. USB IR bridging devices or hubs will resolve many of these physical placement issues.
A USB working group is developing guidelines on how USB will interface with both IrDA and Control IR devices, with first products expected to ship around the middle of 1998. These guidelines are expected to address an RF bridge in anticipation of future home RF standards that should emerge and will be required for PC 98 when finalized by the working group.
It is recommended that manufacturers move their wireless designs to incorporate fast IR solutions as soon as possible. Fast IR transmits and receives data at speeds of 1.152 Mb/s and 4.0 Mb/s. Fast IR includes design implementations that improve usability. To minimize interoperability issues, manufacturers need to include Serial IR (SIR) backward compatibility in their fast IR solutions.
Manufacturers who are planning to produce wireless PC peripherals such as keyboards, pointing devices, and joysticks are encouraged to use Control IR instead of RF as the communications medium. The Control IR specification was based on the requirement to support a minimum of four joysticks on systems such as Entertainment PC.
Not using RF will help to minimize RF interference to devices that require between-room communications, such as cordless phones. This recommendation does not apply to wireless PC peripherals used in offices, where RF might be the only viable solution sufficiently diffuse and able to go through barriers, and where it is less important to have an RF connection to a desktop PC in order to support voice and data communications. There might also be a need to use RF in the home environment if IR is not sufficiently diffuse or is unable to bounce around obstacles.
The requirements listed in this section must be met if wireless capabilities are provided in the system. Power management requirements for wireless devices are defined in the “Power Management for I/O Ports and Devices” section later in this chapter.