Apple LaserWriter 12/640 PS - Manual (Page 276)

You make changes to the communication settings with the printer’s
communication switch set in the Normal (in) position. This makes all
communication settings available for changes.
For more information about connecting the printer to LocalTalk, Ethernet,
and parallel ports, see “Connecting the Printer” in Chapter 1. For more
information about setting the communication switch on the printer, see
“Adjusting Communication Settings” in Chapter 1.
1 Choose Configure Port from the Utilities menu.
2 Choose the port settings you want.
m You can set the Parallel interface to PostScript mode, PCL5 mode, or
AutoSelect mode (which automatically senses whether PostScript or PCL5
mode should be selected). You can also set the Parallel protocol to normal,
raw, or TBCP.
m The LocalTalk interface is always set to PostScript mode.
m You can set the EtherTalk interface to PostScript mode or turn it off.
m You can set the NetWare interface to PostScript mode, PCL5 mode,
AutoSelect mode (which automatically senses whether PostScript or PCL5
mode should be selected), or turn it off.
Communication
switch
276 Appendix A