You can connect up to four computers, and select it with a button on the unit. Then you should (theoretically) the computer which has been selected, to be able to drive the printer.
Then the damper:
Only the computer my colleague (Windows XP) to communicate through this unit with the printer, my computer (Vista) on strike, it is printed not one page.
I knew from a friend that you have to pay for these devices that they "may" with Vista. As is explained in the product description that this device "with all operating systems" get along, it gets to me, therefore, only one star.