Need help in developing a VB app about USB hub!

Here is the info I managed to find on this topic:
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How an application accesses a USB device depends on what device driver
Windows has assigned to the device. For example, if the device is a
disk drive, applications can access it like any other drive. They
don't have to know or care whether the drive has a USB or other
interface. It's all handled at a lower level.

Some devices use custom drivers, so to access them you need
documentation for the driver. A typical driver uses CreateFile, then
some combination of ReadFile, WriteFile, and DeviceIOControl API
calls.

If you're developing your own USB device for low/moderate speed I/O,
the human interface device (HID) drivers built into Win9x/2k are an
option. I have example VB code and firmware for HIDs on my USB page:
http://www.lvr.com/usb.htm

Jan Axelson
http://www.lvr.com
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Regards,
Vikram

Vikram at 2007-9-4 >

I'm not sure you actually want to do this.

You cannot directly connect two computers by a USB cable (even though A-A cables do exist). Doing so could cause hardware damage, because both PCs will be trying to supply power to the USB bus. There will almost certainly be a small voltage difference between the two, and with virtually zero resistance in your USB cable, there will be a large current flow.

You could cut the power wires and connect only the signal wires, but that still won't get you anywhere, because both PCs are USB masters.

So you would need a USB device to sit in the middle, and act as a slave to both computers, and route requests between them. I'm not aware of any such commercially-available device. You could likely build it, but assuming that you have Ethernet available, why bother?

-- graham

Graham at 2007-9-4 >