USB Requirements

This section summarizes requirements for Universal Serial Bus. USB is not required in a server system, but if present, it must comply with these requirements.

All USB hardware complies with USB 1.0 specifications

Required

Recommended: USB hardware complies with Universal Serial Bus Specification, Version 1.1 or later.

All USB hardware present on a server system must comply with the Universal Serial Bus Specification, Version 1.0 or later

When a system has more than one host controller, each host controller must provide full bandwidth and isochronous support. Host controllers should be located on PCI to meet this requirement.

USB 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 vary, appropriate icons on both ports and cables are important for user ease-of-use. 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 1.1 specification as follows:

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.

USB devices and drivers support maximum flexibility of hardware interface options

Required

Device and driver designs should provide maximum flexibility of interface options to allow user-preference coordination by the operating system or other resource managers. This flexibility allows graceful use of multiple simultaneous devices and applications in a dynamic environment.

Specifically, devices and drivers:

Recommended: devices should consume bandwidth only when they are being used.

USB host controller complies with OpenHCI or UHCI specification

Required

The host controller must comply with the specifications for either Open Host Controller Interface (OpenHCI; published by Compaq, Microsoft, and National Semiconductor) or Universal HCI (UHCI; published by Intel). Hardware manufacturers who design to one of these specifications are not required to provide an additional device driver for their host controller under the Windows NT operating system.

Multiple OpenHCI and UHCI USB controllers are supported concurrently by the operating system.

System and devices comply with USB power management requirements

Required

The server system must comply with the power management requirements in the Universal Serial Bus Specification, Version 1.0 or later. In addition, USB devices must comply with the Interface Power Management feature in the USB Common Class Specification, Revision 1.0 or later.

USB devices comply with their related USB device class specifications

Required

A USB peripheral that fits into one of the USB device class definitions must comply with the related USB device class specification. USB class drivers in the operating system are implemented to support compliant devices in each particular class. Class driver extensions and WDM allow IHVs to innovate and differentiate their products while still complying with class specifications in their base operational modes.

USB hubs comply with the USB Specification, Version 1.1

Recommended

The Universal Serial Bus Specification, Version 1.1, defines requirements for USB hubs that cover some ambiguities in the original 1.0 specification.

Bus-powered USB hubs provide ports that can be individually power switched

Required

To minimize USB power consumption requirements, bus-powered hubs must provide ports that can be individually power switched. This contributes to the goal of reducing overall system power consumption.