Honor Student
Posts: 2
Member Since: ‎03-19-2009
Message 1 of 3 (3,675 Views)

Difference between front-panel and rear-panel USB ports

I bought a USB-to-parallel cable so I could use my treasured Laserjet 4M+ printer with mynew HP Media-Center PC.  This works fine when I plug the cable into a front-panel USB port, but does NOT work when the cable is plugged into a USB port on the rear of the computer.  Other than this, all USB ports "seem" to operate normally.  But there is evidently some difference between the two kinds of USB port, rear-panel  vs front-panel.  Anyone know anything about this?

Posts: 13,866
Member Since: ‎11-21-2008
Message 2 of 3 (3,663 Views)

Re: Difference between front-panel and rear-panel USB ports

I don't believe that there is any difference between the USB ports on the front panel and the ports in the rear.  I have seen this anomoly many times, however.  For some unknown reason, at least unknown to me, a device that won't work in one USB port, can be plugged into the port next to it and work just fine.  Why?  Like I said, I don't know.  Maybe there is someone on the forum who can answer the question for both of us.

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Associate Professor
Posts: 1,250
Member Since: ‎01-27-2009
Message 3 of 3 (3,650 Views)

Re: Difference between front-panel and rear-panel USB ports

USB can be buggy (hit or miss).  The USB port on my NF4 board may not detect a USB drive after a few insert/remove cycles.  Only fix is to restart windows.  Never come across this anomaly with my P35 board.  Both were clean installs of XP Pro.


Sometimes, one USB port can deliver higher voltage/current than another USB port.  IRQ mapping may also result in detection problem.  The use of an adaptor cable can amplify a compatibility issue.  For best performance and stability, use an adaptor that connect directly to the PCI or PCI-E slot.



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