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I have a UBS-video capture device connected to a computer with a 5 m USB-cable and a powered USB-hub at the end where the device is plugged in. The problem is I get a lot of glitches and freeze even though the output from the usb-hub is 5 V. When I try a shorter cable (2 m) it works fine. But what could be the problem when I know the power output to the device is enough? Is it the signal going back to the computer that is the problem? Does it need extra power that way too? I could try with another usb-hub and three 2 m cables and see if that works but I don't understand why it isn't working allready with one hub?

Current: (PC)<---(5 m USB A/B)--->(USB HUB w/ power)<---(2 m USB A/A)<---(Device)-->(TV)

Other option: (PC)<---(2 m USB)--->(HUB)<---(2 m USB)-->(HUB)<---(2 m USB)<---(Device)-->(TV)

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up vote 0 down vote accepted

It turned out to most likely be a bad cable. When trying a 1,5 m USB A->B combined with a 3 m USB-extension cable it worked just fine. I don't believe 0,5 m would do so much difference. But it could also have been that one of the other cables had one of those coils to filter out transients in the signal. Maybee that was what was needed. Anyway it works know...

More likely it's the hub. I noticed I could use a combination of many usb extension without any hub to power the device and it worked perfectly just like that.

Update: Bought a new USB-hub and it works fine now. Case closed.

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