Main > Main Forum
USB Extension cable and performance
kegger:
If I had to do it again I would go with a powered hub for all my USB controls as I have had issues with U360's dropping out because of power. Currently I have U360's plugged into powered hub with no problems but I had another hub not being powered externally and it gave me issues :cheers:
WhereEaglesDare:
keep in mind though that good powered hubs are pricey, check out ebay.
Beretta:
like was said powered hubs eliminate problems.. however you should'nt have any preformance degridation wiht an extention..
with that said it may not work at all or only half the time.. i believe it's from voltage drop.
usb is so crappy, they should have went with 12v, it's bad enough being stuck on wimpy 5v but even then you only get like .5 amp's.. total weak sauce.
MonMotha:
Well, there's a few problems associated with extensions.
As has been noted, the first is power. Excessively long cables can cause voltage drop on the cable. This is also seen with unpowered hubs. The spec allows for some voltage drop, but not all devices properly accommodate it.
The second is excessive capacitive loading on the data lines. This distorts the data signal and can make recovery impossible. This tends to result in all sorts of intermittent problems or it just won't work at all even though the device gets power. This is the principle reason the spec disallows long cable runs and extension cables (since they can be used to create an excessively long cable run). You're usually OK as long as the total cable length does not exceed 12ft even if an extension is present, but it's technically against the spec.
You're right, USB is a terrible standard. The 5V thing is annoying, and the fact that you only get 2.5W is also annoying. It's enough to cause damage, but it's not enough to actually run anything big. It should have been limited to either ~1W (low power devices like flash drives) for safety reasons or extended to about 25W to be able to run things like hard drives, printers, scanners, etc. This is of course unrelated to the driver/software model it uses which I won't even begin to get into :) About the only thing USB got right was the HID standard. It's not too bad, and it's very flexible.
R0UNDEYEZ:
--- Quote ---It should have been limited to either ~1W (low power devices like flash drives) for safety reasons or extended to about 25W to be able to run things like hard drives, printers, scanners, etc.
--- End quote ---
as nice as that would be, where is all this power coming from? i think the average user probably uses stock power supplies that have 350w tops that is already running everything (processor, motherboard,harddrives,optical drives, fans etc) having a standard that would allow them to draw over 100 watts off a single run of the mill hub seems like asking for problems to me, plus you know how people are with extension cables and adding extensions to extensions haha
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version