[olug] Firewire PCI cards

Christopher Cashell topher at zyp.org
Fri May 14 09:00:32 UTC 2004


At Thu, 13 May 04, Unidentified Flying Banana Ryan O'Rourke, said:
> I'm buying one of those combo Firewire and USB 2.0 PCI cards this
> weekend so I can start video conferencing with a webcam.

[Snip.]

Just a quick little notice or warning to people, for when you buy USB
2.0 devices. . . Always read the product information *very* carefully.
USB 2.0 does *not* guarantee that a device uses the high speed 480Mb/s
spec.

USB 2.0 actually supplies specifications for three USB speeds, Low-Speed
(1.5Mb/s), Full-Speed (12Mb/s) and High-Speed (480Mb/s).  Things like
keyboards and mice use the Low-Speed spec, as they have no need for
higher bandwidth.  Ideally, NIC's, cameras, pen drives, etc, will use
the High-Speed spec.  Things that require more bandwidth than 1.5Mb/s,
but don't need more than 12, will continue using the Full-Speed spec.

Just be careful, though, because there are a number of unscrupulous
device manufacturers that are marketing "USB 2.0" devices that use the
Full-Speed bandwidth spec.  I have a friend who's already gotten burned
on this, buying a device that was advertised as USB 2.0, but only in the
small print does it mention that its bandwidth is only 12Mb/s.

Look for the "High-Speed USB" graphic, or check the fine print
information to make sure you're getting what you think you are.

> -- Ryan

-- 
| Christopher
+------------------------------------------------+
| Here I stand.  I can do no other.              |
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