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mactropolis · Jan 14, 2005, 01:37 AM

Hello,
I was doing some planning for my next Mac purchase (finally...my headless Mac is here), and I was wondering about USB 2.0 powered hubs. The Mac Mini has just 2 USB 2.0 ports: one of which will be used for keyboard & mouse, leaving a single port available. Since I have a bunch of other USB devices, I realized I would have to get a powered USB 2.0 hub. I would like to know how the speed is affected when I mix USB 2.0 and USB 1.1 devices on that powered USB 2.0 hub. For example, I have a USB (1.1) printer (needs USB power), a USB (1.1) Floppy disk drive (needs USB power), and a USB 2.0 Flash drive. If I were to plug all 3 in simultaneously into a powered USB 2.0 hub, would I be able to use USB 2.0 Flash drive at Hi-Speed or USB 1.1 speed? If it does degrade the USB 2.0 device to USB 1.1, should I just get a cheaper USB 1.1 powered hub?

Thx.I.A.

mactropolis · Jan 14, 2005, 08:16 AM

Doesn't anybody know about USB 2.0??

effgee · Jan 14, 2005, 08:30 AM

Originally posted by mactropolis:
Doesn't anybody know about USB 2.0??

Might have been a good idea to post this in the peripherals forum - but here we go ...

Yes, as soon as you plug in a USB 1.1 device into your USB 2 hub, everything connected to it will fall back to USB 1.1 speeds. My advice is to get two powered USB 2 hubs (I haven't seen 1.1 hubs in any store for a while now and the v.2 hubs can't be that more expensive), use 1 exclusively for all your USB 1.1 devices (including keyboard and mouse) and the other one for all your USB 2 stuff so you can take advantage of the extra speed.

HTH

Severed Hand of Skywalker · Jan 14, 2005, 12:40 PM

Originally posted by effgee:

Might have been a good idea to post this in the peripherals forum - but here we go ...

Yes, as soon as you plug in a USB 1.1 device into your USB 2 hub, everything connected to it will fall back to USB 1.1 speeds. My advice is to get two powered USB 2 hubs (I haven't seen 1.1 hubs in any store for a while now and the v.2 hubs can't be that more expensive), use 1 exclusively for all your USB 1.1 devices (including keyboard and mouse) and the other one for all your USB 2 stuff so you can take advantage of the extra speed.

HTH

I was going to say the same thing. They still sell 1.0 hubs like crazy so get one USB 1 hub and one USB2 hub. Pain but that is what you have to do.

tooki · Jan 15, 2005, 01:51 AM

Originally posted by effgee:
Yes, as soon as you plug in a USB 1.1 device into your USB 2 hub, everything connected to it will fall back to USB 1.1 speeds.

But that's not true. I have a USB 2 hub, and I mix-and-match devices, and the USB 2 devices continue to run at 480Mbps.

tooki

effgee · Jan 15, 2005, 06:52 AM

Originally posted by tooki:
But that's not true. I have a USB 2 hub, and I mix-and-match devices, and the USB 2 devices continue to run at 480Mbps.

That's wacky. When buying my USB2 hub (D-Link) a while ago, I remember the manual (same thing as mentioned in this thread) stating that connecting USB1 connected devices to the hub would/could(? - can't Intel do anything right??) bring down the speed for all devices connected to the hub. I also remember reading a similar statement on some Mac site some time ago (no idea when and where, though). Maybe something that's specific to this particular D-Link hub? That would be an interesting tidbit - if only because so far, I had a fairly good opinion of D-Link products. Ugly as sin and certainly not premium quality but decent performance/features for the price.

I have an external HD case with FW400/800/USB2 ports lying around - if I have some time today I'll stick a spare HD in there and take a peek if/how/how fast that works with my hub.

tooki · Jan 15, 2005, 12:44 PM

I can totally see it depending on the chip design used in the hub. It's eminently possible that some hubs (especially older ones, I would imagine) can't handle speed arbitration.

But here's another reason why I don't buy the "you can't mix and match speeds" argument: even USB 1.1 has multiple speeds. You've always been able to mix and match "low speed" and "full speed" devices, and all that USB 2 does is to add a third speed, "high speed" to the mix.

tooki

turtle777 · Jan 15, 2005, 08:39 PM

Originally posted by tooki:
I can totally see it depending on the chip design used in the hub. It's eminently possible that some hubs (especially older ones, I would imagine) can't handle speed arbitration.

But here's another reason why I don't buy the "you can't mix and match speeds" argument: even USB 1.1 has multiple speeds. You've always been able to mix and match "low speed" and "full speed" devices, and all that USB 2 does is to add a third speed, "high speed" to the mix.

tooki

What is the make of your USB hub ?

-t

mactropolis · Jan 17, 2005, 08:27 PM

I greatly appreciate all the info and advice.

Thanks.

tooki · Jan 17, 2005, 09:11 PM

Originally posted by turtle777:
What is the make of your USB hub ?

-t

Mine's a little cheap GE-branded "travel" hub (comes with a power adapter, but will work unpowered as well; note that the page's tech specs are wrong, it supports 480Mbps mode). I've seen the same exact unit sold by several other brands, though.

tooki

effgee · Jan 18, 2005, 04:32 AM

Originally posted by tooki:
But that's not true. I have a USB 2 hub, and I mix-and-match devices, and the USB 2 devices continue to run at 480Mbps.

Spent a few more minutes reading up on this over the past two days and, according to the official USB specs, Tooki is right. USB2 hubs (they're actually built more like a router and thus aren't really hubs, despite their "street" designation) are supposed to support all 3 speeds (1.5, 12 and 480 mbps) simultaneously.

So much for theoretical specs - because from what I read online and judging from my own experience with the already mentioned D-Link hub, actually achieving these speeds is a different matter that seems dependent on quite a few factors such as the hub itself (in terms of how good/bad the quality of the parts used by the mfr.), the cables you use, length of the cables, etc.

I did check whether my D-Link hub would support decent transfer rates from an external HD to my desktop machine and it definitley does not. I had planned on buying a second hub for a while now anyway so I went to the store yesterday and got me a (hopefully decent, since it was rather expensive) Belkin hub - I'll try the "speed test" again sometime later this week.

Somehow this reminds me (a bit) of some of the weird peripherals experiences I used to have in the good old days of SCSI.