computer-to-computer communication over USB

[Joseph Mack NA3T]

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


-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml 
Homepage http://www.austintek.com/ It's GNU/Linux!