[072707]

Yesterday I "daisy-chained"(added) a second powered 4-port USB 2.0 hub to my Inspiron 8500 xp sp2 laptop. I experienced various system problems until, finally, after using 2 different hubs that I had around, I suspected that the second hub should be run w/out its own ac adapter plugged in.

In other words, just my first hub(the one that is directly connected to the computer) is plugged in to the wall outlet.

Since I took the aforementioned action I have experienced no system problems while running the two "daisy-chained" 4-port USB hubs.

I presume that if I add additional hubs to the same machine then they will all have to be run w/out their own ac power as well. Am I correct? [Just use ac power on the one USB hub that is connected to the computer...? Not the subsequent ones that are connected to a hub...?]

Additionally, the powered 4-port USB 2.0 hub cost me much more money than a regular non-powered hub. Since I am running the second hub w/out its own power anyway can I put a regular non-powered hub in its place, even if that hub is not 2.0, with no decrease in performance?

That raises another question that I don't know the answer to. Can USB hubs that are manufactured with no independent ac adapter ever be 2.0 or are they all not 2.0, by definition, since they don't have their own power supply capability?

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For laptops all hubs should be powered ones, because a laptop cannot provide enough power to run a hub on its own. Desktops with a big enough power supply can theoretically run as many USB hubs as you care to feed them, but laptops need the extra power.

You should be able to get away with just using the one AC adaptor for all the hubs if they're daisy-chained together. Non-powered hubs are designed to run from the power provided by the computer so in theory using it in a typical daisy-chain setup should work. You'll have to try it though.

Most hubs these days are USB 2, the major sticking point would be the USB ports on your laptop. If they aren't USB 2, none of the others will be.

[Neil Jones]

For laptops all hubs should be powered ones, because a laptop cannot provide enough power to run a hub on its own. Desktops with a big enough power supply can theoretically run as many USB hubs as you care to feed them, but laptops need the extra power.

You should be able to get away with just using the one AC adaptor for all the hubs if they're daisy-chained together. Non-powered hubs are designed to run from the power provided by the computer so in theory using it in a typical daisy-chain setup should work. You'll have to try it though.

Most hubs these days are USB 2, the major sticking point would be the USB ports on your laptop. If they aren't USB 2, none of the others will be.