Re: Multiple USB 1.1 devices in USB 2 Hub speed ?
- From: "Peter Petersen" <pp@xxxxxxxxxx>
- Date: Thu, 17 Jul 2008 09:23:42 +0200
Hello Anton,
If I have a number of USB 1.1 devices plugged into a USB 2 Hub, can I
get the full 12MB/s of each USB 1.1 device via the USB 2 link
Yes.
Or does the USB 2 link fall back to a 1.1 compatible mode ?
No. It would do that with a full speed Hub, but not with a high speed
(2.0) Hub.
All the other posts in this thread are wrong. A USB 2.0 hub is an
intelligent device which will repack the high speed communication coming
from the host and resend it as full/low speed on its downstream ports.
If you want to read about the details, see sections 11.1.1 and 11.14 of the
USB 2.0 Spec (Hub Transaction Translator). USB 2.0 Hubs must be able to
translate between high speed hosts and low/full speed donwstream devices.
So if I need to combine 6 full speed devices into one High speed
channel, I would need something with 6 1.1 host ports and one 2.0
device port.
You need one high speed port on your host and one high speed Hub with 6
downstream ports.
Peter
.
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