I have a case with two wired devices with network connections.  Downstairs, 
we have a computer which is connected to an ADSL router via cable.    Then, 
upstairs, there is going to be a networked printer.
The problem is, running the network cable to connect this printer from 
upstairs into the router is not decoratively acceptable.  Its an old house.  
So I have bought one of those little wireless usb adaptors, and we happen 
to have an old wireless cable router lying around.
The idea would be, wire the printer into the wireless router upstairs, then 
talk to the wireless router over wireless from the usb adaptor in the 
computer downstairs.
This would be two network connections from the same computer, one wired, 
the other wireless, with the wireless one going only to the printer, and 
the wired one going to the ADSL router for Internet access.
This must be possible, you would think, but how do you set it up?
I had intended to use homeplug, ethernet over mains, but the problem is 
that the two parts of this particular house are on different mains supplies 
with separate meters.  Its an old house.  Also, I can't move the ADSL 
router upstairs, because there are no phone sockets upstairs. They use 
cordless phones. 
So assuming its possible, the simplest would be wireless to the printer 
only.  So this would be using eth0 for Internet access, and eth1 for 
printing only.  Can you do this, and if so how?
Peter