Scanner recommendations needed

[Chris Adams]

Once upon a time, Fred Smith <fredex at fcshome.stoneham.ma.us> said:
> It IS USB, and one caveat is that it doesn't work well (or at all) if you
> use a very long USB cable. The provided cable works, though may not be
> long enough, depending on where/how youwant to place it. It also works
> with an extension cable of 4-5 feet. but if you add on a ten foot cable,
> you can kiss it goodbye.
> 
> some googling informed me that the max recommended cable lengths for
> USB devices is based not on signal degradation over the length of the
> wires, but on signal timing,... the timings are so tight that the 
> speed of light is the causative element for max cable lengths.

I doubt that timing is the problem.  The speed of signal propagation
through a copper wire is IIRC around .5c, so the delay added by an
additional 4 feet of cable is only about 8ns.  Timings on USB are
measure in µs; a few ns is not going to make a difference.

Much more likely is that you are talking about a USB bus-powered device
and the voltage drop across your cable was too high, so the device
didn't get enough power.  This is a common problem with cheap USB
cables.  If you use a USB cable with larger-gauge wire, you should be
fine.
-- 
Chris Adams <linux at cmadams.net>