HP Professional AP500 Compaq Professional Workstation AP500 Key Technologies W - Page 18

WHITE PAPER (cont'd) Compaq Workstations - Key Technologies • Electrical system gain staging. Gain staging is a key process in transforming the individual piece parts into a unified audio system. Gain staging allows Compaq to compensate for the audio sources, such different input levels that as CD-ROM, wavetable, are and generated line in. by a numLbOerUoDf SdPifEfeAreKnEt R The end result of the interaction between the susbystems is a well balanced, "no desktop clutter," audio system capable of delivering clean, undistorted output at a level needed to support an office environment. UNIVERSAL SERIAL BUS (USB) The Compaq Professional Workstation AP500 includes two Universal Serial Bus (USB) ports. USB is a peripheral bus standard developed by a group of PC and telecom industry leaders including Compaq, DEC, IBM, Intel, Microsoft, NEC and NORTEL. USB enables hot plug and play of computer peripherals outside of the workstation eliminating the need to install boards into expansion slots and then having to reconfigure the system. Workstations equipped with USB allow peripheral devices to be automatically configured as soon as they are physically attached, without the need to reboot or run setup. USB also allows up to 127 devices to run simultaneously with peripherals such as monitors and keyboards acting as additional plug-in sites or hubs. USB peripherals include telephones, modems, keyboards, mice, CD-ROM drives, joysticks, tape and diskette drives, scanners, and printers. USB has a 12 Mbits/s data rate, compared to 115.2 Kb/s for serial ports and 2 Mb/s for enhanced parallel ports. This improved transfer rate will accommodate a new generation of peripherals, including MPEG-2 (compressed data) video-based products and digitizers. Drawing its intelligence from the host workstation, USB detects when devices are added and removed. USB automatically determines what host resource each peripheral needs, including driver software and bus bandwidth, and makes those resources available without user intervention. Currently, there are different ways to implement USB. The Compaq Professional Workstation AP500 implements the OpenHCI USB interface. OpenHCI reduces CPU overhead for USB devices compared to other implementations and is fully compatible with UniversalHCI. Currently, Windows NT Workstation 4.0 does not support USB, but future versions are expected to include USB drivers that will allow the workstation to recognize USB peripherals. 18