PA-RISC Visualize Workstation Universal Serial Bus
Table Of Contents
What is USB?
• U.S.B. stands for Universal Serial Bus (Logo: Icon: )
• Moderate speed 12 Mbps/sec. or 1.5 Mbytes/sec.
• Multiple devices up to 126 - on a single resource set.
• Cubicle span cabling 5m per segment, 30m max. with hubs
• Flexible topology tiered star
• Flexible power devices bus- or locally-powered, w/suspend-resume APM
• Robust PnP, hot attach-detach
1
• Low-cost 4 wire
• Idiot-proof Unique modular connectors:
Style A (upstream, to hub/host):
Style B (downstream, detach at device):
Although USB ports have been shipping on PCs for over two years,
widespread acceptance has been delayed by lack of
devices, which, in turn, have been awaiting:
• O.S. support: Still waiting for “NT”. Win95 support is problematic.
• BIOS support: Most “USB” PCs have no USB console capability in BIOS.
• Economics: Some PS/2 devices are still cheaper than USB during 1999.
1. Hot attach-detach is planned, but not fully implemented in the first HP-UX USB support.
A
B