When setting up the Color LaserWriter 12/600 PS or the Color LaserWriter 12/660 PS printer to print from MS-DOS the printer is connected using LPT1.DOS. With this configuration the drivers for the Color LaserWriter 12/600 PS will not let you change the PostScript settings for the printer. To resolve this issue connect the printer to LPT1, make the appropriate changes in the PostScript section of the drivers setup. Then go back and change the connection settings to LPT1.DOS.