The AF142 is a reversable Bitronics Auto Switch that will operate in either, one computer to two printers mode, or two computers to one printer mode, called respectively 1 to 2 mode and 2 to 1 mode. These switches operate in 2 to 1 mode without software drivers and deliver print jobs to the printer on a first come, first served basis. This means that if one computer is printing to the printer the other computer must wait for the Auto Switch to finish the current print job. The AF142, when operating in 1 to 2 mode, uses the AS Ware driver to select which printer of the attached to the Auto Switch will print the print job. You can only be printing to one printer at a time unless both printers are identical and you wish to rapidly produce many copies of the same document. The AF142 can go into a unique "broadcast" mode and both printers will print the exact same document, leaving you with two copies.