This program, LPTSWAP, switches from one parallel port to another, redirecting PRN output from LPT1: to LPT2: and then back again if you run it again. It merely says where PRN is routed to, LPT1 to LPT2 or LPT1 to LPT1 by saying it's not redirected or some such. Easy as pie to use, and if you have two parallel interface printers and two parallel ports, it's about all you need instead of one of those silly A-B switches that are overpriced. The extra port is a better value.
fred1144