pls help

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hi,
 
Does the USB driver which you get along with Windows2000 DDK, support
multiple devices?

My next doubt is regarding USB on Application side.
Is there any way of ditinguishing between say 120 USB devices of the
same family connected to my system via hubs. Like .... You can
distinguish different COM ports like "COM1", "Com2" etc.

Is there any similar way of making out between 120 USB devices??

pls help.

Re: pls help
Hi,
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as i remember USB endpoints under 255 number set host by initialization.

Cheers

Re: pls help
hi,
 thanks a lot for your help.
Neo.


snipped-for-privacy@yahoo.com (Vic) wrote in message
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Re: pls help
snipped-for-privacy@mistralsoftware.com (Neo) wrote in message
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Yes.

Windows assigns each device a unique name based on its
location and serial number.  Than name is stored in the
registry and remains constant between boots.  But it is
not a particularly friendly name as it contains a GUID
and other distinguishing information.  This name is also
not formatted the same in different versions of Windows.
If you're writing the driver for the device, you can
generate a friendly name for it.

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Look into the Microsoft documentation for the SetupDiXXX()
function group.  Also you won't be able to do 120 devices
because of the number of hubs required.

Re: pls help
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Not all drivers support multiple devices with identical VID/PID, but
many do. I don't know what driver you're referring to.

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The application retrieves a handle for each device. If you need to
keep track of which device is which even if you move the the devices
to other ports or power down, then back up, store a unique serial
number in each device's descriptors.

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With this many devices, identical or not, you can run into bandwidth
limits or scheduling problems (depending on the quantity of data and
transfer types).

Jan Axelson
www.Lvr.com

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