To interface a LaserWriter with an IBM compatible, WordPerfect 4.2, which now
claims support for the LaserWriter, furnishes a segment of PostSript code with
the file name INITWRT.PS. This file, according to their instructions, is to be
sent to the printer via the serial port to change the EEROM so that the
LaserWriter will thereafter support a hardware protocol, specifically DTR.
Leaving out the comments and password checking, the essential PostScript code
that is sent to the LaserWriter is
25 9600 7 SETSCCBATCH
The channel and baud numbers are default, but the LaserWriter Technical manual
mentions only integers 0 through 3 for the parity position and mentions
nothing about 7.
The code would have no effect on the AppleTalk Network. This code makes changes
strictly in the LaserWriter and then only where specified by the code (batch
or interactive). This code does not affect the "SPECIAL" mode. SCCBATCH is only
for the "9600" or "1200" switch positions in Diablo emulation mode for using
PostScript with the printer. The "SPECIAL" mode is controlled by
SCCINTERACTIVE, and the line
25 9600 7 SETSCCINTERACTIVE.
could control the Diablo 630 mode functions under 9600 and DTR protocol.
The only problem is that unless the user has a LaserWriter Plus or a
LaserWriter with 2.0 (or later) ROMs in it, this "7" command is useless. Since
the LaserWriter only supports Xon/Xoff flow control, any command sent to set up
DTR handshaking will not function, and there may actually be some strange
actions from the printer if it is attempted. If they don't have 2.0 or later
ROMs in their LaserWriter, do not use this code.