Tech Support > Microsoft Windows > Device Not Recognized Error with usb cable 15 m long
Device Not Recognized Error with usb cable 15 m long
Posted by Bernard Goh on March 23rd, 2006


Hi All,

I got this Device Not Recognized error when I connect a USB Flash Drive
15meters away in a another room. I have tested my equipment with the
following scenerio for possible cause:

1. Connect the flash drive with a shorter cable. -- It works.
2. Connect the flash drive with the 15M long cable to another PC (Windows XP
Pro no secvice packs) -- It works. (with the 15meters usb cable)
3. Check the USB Controller Status -- All 4 of them report working correctly
4. Reinstall the software for USB controller (Intel (R) 82801GB USB
Universal Host Controller 27C8) -- Same Error.
5. Try all 4 usb ports I have -- None is working with the 15m usb cable.

Following is my PCs configuration
HP Compaq dx7200 Minitower PC
Windows XP Professional Sevice Packs 2 (with all lastest updates installed)
Norton Antivirus 2005

What has gone wrong ? any help is very much appreciated.

Many Thanks In Advance,
Bernard Goh
IT Administrator
Success Electronics & Transformer Manufacturer Sdn Bhd
No.5 & 7,Jalan TSB 8
Taman Industri Sg. Buloh
47000 Sg.Buloh
Selangor Darul Ehsan


Posted by ERICCASEY on March 23rd, 2006



Have you tried connecting the drive, then reboot the machine, to see if it
picks it up on the reboot?
On the machine that it works for have your tried to do a reformat under
computer management?

Posted by John Wunderlich on March 23rd, 2006


"Bernard Goh" <bghs312@hotmail.com> wrote in
news:OU7u1MkTGHA.5552@TK2MSFTNGP14.phx.gbl:

The USB Specification limits the length of a USB Cable to 5 meters.
For more info, see "USB Frequently Asked Questions", "Why are the cable
length limits what are they?"

<http://www.usb.org/developers/usbfaq/#cab1>

HTH,
John

Posted by Don Taylor on March 23rd, 2006


"Bernard Goh" <bghs312@hotmail.com> writes:
It has been a while since I was in that, but at the time
the maximum cable length five meters, and in some cases
had to be even shorter than that. Timing was critical
and signals often just didn't make the trip in time for
cables longer than that. Longer than that and it was
anybodies guess whether it might work, and it usually didn't.

Then they added in hubs and repeaters, but there is a limit
on how many of those you can have.

So my guess, you are outside of specifications to begin with.
Some quirk of the software timing happened to let it work
with one version and it doesn't work with another. That it
works just fine with a short (in spec) cable seems to confirm.

Try a repeater and see if that will make it work.


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