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>>>>>> Sounds like it's a 1.1 device to me. |
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>>>>> |
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>>>>> Yep, that's what it sounds like to me too. |
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>>>>> |
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>>>>> Dale |
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>>>> |
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>>>> But that's OK isn't it? I don't need 2.0 speeds between each webcam |
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>>>> and the controller, I just need the increased overall bandwidth of a |
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>>>> 2.0 controller so one of the 1.1 webcams doesn't use all of it. |
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>>> |
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>>> The 2.0 controller doesn't _have_ increased bandwith if it's |
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>>> talking to 1.1 devices. In that case, the 2.0 controller is |
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>>> transferring data at the same speed as a 1.1 controller. |
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>> |
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>> I thought the total bandwidth available for a controller was different |
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>> than the bandwidth at which it communicates with one device. You're |
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>> saying any 1.1 device that uses 12 mbit/s will 100% monopolize a 2.0 |
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>> controller so no other devices can function? |
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>> |
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> |
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> Yes. USB is not like 1394/Firewire. Firewire will increase and |
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> decrease bandwidth as different devices take control of the bus. There |
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> is negotiation between devices and the device that owns the bus |
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> controls how the bus is used. |
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> |
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> With USB a 1.1 device on the bus causes the 2.0 controller to operate |
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> at 1.1 speed so there is only 12Mb/S on that bus once you plug the 1.1 |
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> web cam in. |
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> |
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>> Taking a different approach, since I have 2 USB controllers (EHCIx1, |
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>> OHCIx1) why can't I operate one webcam on one controller and one |
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>> webcam on the other controller so they can both function? |
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>> |
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> |
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> If the hardware is working correctly, if the drivers are independent, |
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> and IF IF IF the two physical ports you chose are actually going to |
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> completely different controllers then you can. I do this. This sort of |
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> thing becomes an issue with USB when you make a mistake an plug an old |
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> USB mouse or keyboard into the wrong physical port and bring your 2.0 |
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> bus speed down to 1.1 bandwidth. |
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|
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That's a lot of IFs. This USB PCI card looks good because it claims: |
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|
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"Five ports in three independent host controller design, two OHCI and one EHCI" |
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http://www.newegg.com/Product/Product.aspx?Item=N82E16815104202 |
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|
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Are you saying I can't count on this card behaving as 3 separate USB |
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controllers? |
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|
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- Grant |
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|
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|
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> Over and out, |
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> Mark |
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> |
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>> - Grant |
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>> |
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>>>> I get the feeling I have a misconception somewhere along the |
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>>>> line here. Could someone straighten me out? |
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>>> |
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>>> A Corvette going 3MPH will get to the finish line at exactly |
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>>> the same time as a 4-year-old kid on a tricycle going 3MPH. It |
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>>> doesn't matter what the controller is capable of -- it matters |
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>>> what speed it's actually talking. |
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>>> |
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>>> -- |
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>>> Grant |