Re: Which USB hub
- From: phil-news-nospam@xxxxxxxx
- Date: 27 Jul 2008 21:05:08 GMT
On Sun, 27 Jul 2008 21:26:59 +0200 Johannes Beekhuizen <jbeekhui@xxxxxxxxxxx> wrote:
| With or without power supply?
If you want to power devices plugged into the hub, I believe it will need
a power supply of its own. I have a couple hubs with memory card adaptor
intergrated and it does the hub thing and the memory card thing entirely
on power from the PC (or presumably uptream hub if I cascaded them). If I
plug in a self powered USB hard drive, it works w/o the hub P/S. If I plug
in a memory card, it works w/o the hub P/S. If I plug in a USB flash key,
it does NOT work unless the hub P/S is plugged in and energized. I suspect
they simply wired it this way under the assumption of low power usage by
memory cards (cards plus hub logic won't exceed the 1/2 amp from the PC)
and _possible_ high power usage from the USB port (some other device might
want all 1/2 amp allowed, despite a USB key not needing that much, and that
would exceed the upstream power availability).
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- References:
- Which USB hub
- From: Johannes Beekhuizen
- Which USB hub
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