The factory default settings for the parallel port is TBCP (binary). However, each time the Configuration switch on the printer is changed the protocol TBCP inadvertently gets changed to Normal (ASCII), which is why image data, which is typically binary data, cannot be printed.
Fortunately, you can easily work around this problem by either resetting the protocol on the printer or by configuring your PC to print all jobs in ASCII.
To Reset Printer's Protocol:
1. Relocate the configuration switch back to its default position (to the right; refer to page 40 in the Apple Color LaserWriter 12/600 PS manual).
2. Reset the protocol back to TBCP via the Macintosh or Windows version of the Apple Printer Utility. (Note: If you are use the Apple Printer Utility for Windows that came with your printer, restart your PC before printing or launching the Apple Printer Utility again.)
To Configure the PC to Print ASCII:
1. In the Printer Control panel click on Setup,.
2. Select Apple Color LW 12/600 PS.
3. Click on the PostScript subheading, then deselect Send Data In Binary checkbox.
Thereafter, all print jobs will be sent to the printer in ASCII, including graphical data, which the Normal protocol accepts.
Upgrading ROMs
The parallel communications printing difficulty described above exists only with Apple Color LaserWriter 12/600 PS printers having v1.0 ROMs.
Therefore, a third option exists for resolving the situation. Obtain the Color LaserWriter v2.0 ROM upgrade, service part number 076-0621. This ROM upgrade may be purchased from your service provider.