computer-to-computer communication over USB

[Brian Henning]

Joe,
   A PC-to-PC USB connection is possible, but it requires active 
electronics along the way; although adapters are sold which can 
passively produce a USB cable with Type-A Male plugs on both ends, if 
you plug two computers together like that you'll melt stuff and/or 
release the magic smoke.
   What you need is (I think) called a USB Bridge.  Check out...
<disclaimer> This is NOT a product plug or endorsement.  This is simply 
a result I found with 30 seconds of googling for "USB bridge".  I have 
no idea if this particular product, or company, is any good.</disclaimer>

http://www.sewelld.com/UsbCable.asp

At any rate, you'll notice the lump in the middle of the cable in the 
picture; that's the important bit for making such a connection.

According to the product description on that site, that package includes 
software for transferring files; however, I'm sure it doesn't include 
software for doing exactly what you want to do..  Perhaps someone else 
can offer insight into the possibility of achieving your ultimate goal.

Cheers,
~Brian

Joseph Mack NA3T wrote:
> For school, my 10yr old son has an AlphaSmart. It's a battery powered 
> keyboard with a (about) 10 line x 40 char LCD screen with an editor and 
> enough memory to produce files of several pages of text. To a desktop 
> machine it appears to be a USB HID keyboard. The AlphaSmart has the 
> square USB plug and you connect the two machines by a USB cable. On the 
> desktop machine you open up your editor and on the AlphaSmart you hit 
> "send file" and the text appears on the desktop machine in the editor 
> window.
> 
> I was wondering if it's possible to replace the AlphaSmart by a laptop 
> computer and have the laptop look like a USB keyboard to the desktop 
> machine. The first problem I see is that both the desktop and the laptop 
> machine are USB hosts. Can they talk to each other or can a USB host 
> only talk to a USB client (or whatever the other end of USB is called)? 
> Do you need a null modem type cable? Assuming I can solve this problem I 
> still don't have any idea how to turn a laptop into a USB keyboard. 
> Since I can't fiddle with the desktop machine at my son's school, the 
> laptop would have to appear to be a USB keyboard, ie I can't do tcpip 
> over USB (if that exists).
> 
> Thanks Joe
> 
>