This section summarizes the basic USB design requirements.
1. USB included on PC 98 system
Required
This is required for all PC 98 system types. As noted in the “Basic PC 98” chapter in Part 2 of this guide, BIOS boot support is required when a USB keyboard is the sole keyboard support provided with the PC system.
2. All USB hardware complies with USB 1.0 specification
Required
All USB hardware must comply with USB Specification, Version 1.0 or higher, published by Compaq, Digital Equipment, IBM, Intel, Microsoft, NEC, and Nortel. This ensures that USB hardware has complete Plug and Play capabilities and is implemented in a standard way.
For example, on any system with USB capabilities, a user must be able to dynamically attach any USB peripheral to any USB connector. The operating system should automatically recognize it, load and initialize the appropriate drivers, and make the device available for use.
3. Connections use USB icon
Required
The icon can be molded, printed, or affixed as a permanent sticker. Because the location and number of USB ports can be vary, appropriate icons on both ports and cables are important ease-of-use factors. Therefore, USB icons are required for external cables, connecting cables, and connection ports.
Icons can be based on vendor designs, or vendors can use the recommended USB icon defined in Chapter 6 of the USB 1.0 specification and illustrated here:
The USB icon should be molded into the connector and also placed on the product for ease of identifying the USB port. It is recommended that the icon on the product and the one on the plug be adjacent to each other when the plug and receptacle are mated. This icon can be used for both series A and B connector schemes. On the plug, there should be a 0.635-mm rectangular recessed area around the icon such that there is a perceptible feel of the icon.
4. Devices and drivers support maximum flexibility of hardware interface options
Recommended
Device and driver designs must provide maximum flexibility of interface options in order to allow user-preference coordination by the operating system or other resource managers. This will allow graceful use of multiple simultaneous devices and applications in a dynamic environment.
Specifically, devices with configurations or interfaces that contain isochronous endpoints should not consume any USB bandwidth when the device is first configured. This can be done by having the zero AltSetting for any interface consume no bandwidth. When the device is put into operation, the device driver should switch the device to an AltSetting that allocates and consumes the required amount of bandwidth. When the device is no longer being used, the driver should return the device to an AltSetting where bandwidth is not consumed.