USB 2 Hubs

[Bob Harris]

I'm curious as to the consensus of opinion on this site regarding the use of USB Hubs versus connection directly to the Motherboard's USB 2 outputs, or adding a PCI USB 2 card. I have had some difficulty with various devices that connect to a 7 port Belkin hub. These same devices will work if connected directly to the MB USB 2 outputs. The items having trouble with the hub have been flash drives and a DVD-RW drive mounted in an external box. A scanner and two external HDDs have no trouble going through the external hub. The hub is powered, so I don't understand why there should be a problem.

If one installs a PCI USB card, I'm wondering if the the behavior will resemble the hub, or will items work as though they were connected to the MB? My particular MB is an ASUS P4PE and has only 4 USB ports on the back. Incidentally, the bios on this MB allows for a variable USB voltage: Low, Medium, High, and very high. I've generally kept it at "medium".

Just wondering what the thoughts might be. It wouldn't be worth a new MB just for this kind of an issue.

Thanks a lot for any thoughts.

--Bob Harris

[JoeP517]

That would seem to be a power problem. Are you trying to have all 5 devices in the hub at one time? Have you checked the aggregate power used by the devices to see that it is within the range of the hub? Does the order in which they are plugged into the hub make any difference? Does removing the scanner or external HDs make any difference?

Joe

[Bob Harris]

Thanks for the reply, Joe. Actually, at the time I was having the difficulty with the external DVD-RW it was the only item that was on. The others were turned off. I've had this situation before. I got the DVD-RW to work by plugging it directly into a port on the MB (the only one left).

I had wondered about voltage as well, so I increased the voltage level in the MB bios to maximum and tried the thing today. It worked OK. If that settles it, then all is well. However, I would have thought with a powered hub the voltage from the MB would not be an issue.

Another reason for my question is that I've seen others on other forums complain about this same type of phenomenon. So, I'm kind of curious as to the consensus relative to USB and how much you can really pile on any one port; powered hub or not. In theory (underline THEORY), I think 127 devices are supposed to be possible per port.. ?

Thanks again for your response and thoughts on this issue.

--Bob <img src=/S/flags/USA.gif border=0 alt=USA width=30 height=18> <img src=/S/flags/California.gif border=0 alt=California width=30 height=18>

[JoeP517]

Bob,

You may want to go to USB.org - Frequently Asked Questions for more information.

Joe

[LegareColeman]

Devices that are turned off can still draw power from the hub. The only way to be sure is to unplug the devices from the hub.

There are two things that I have encountered when connecting devices to a hub. One is the power problem that has already been discussed. Some hubs, even though powered, seem to have very low capacity to provide power to connected devices. If you have a hub from a different manufacturer, you might want to try it.

The second problem I have seen is device drivers that don't handle the hub correctly. You might want to check the web site for the device that you are having problems with for more current drivers.

[DaveA]

Make sure that the HUB version is the same as the mother board version, Version 1 vs, version 2. Then there are the version 2 devices that have problems running on a version 1 hub and even sometime on the mother board.