The LaserWriter IINTX manual states that the printer can be set for higher
speeds (beyond 9600 bps), but the IBM PC/AT serial port can be set only to
9600 baud on some versions of DOS. Only versions 4.00 and greater of DOS
have an option for 19,200 baud (the current upper limit). Although ATs and
386 systems can be programmed to handle faster rates, any application
accessing the serial ports through DOS is restricted to DOS Mode Command
options.
There are two ways to handle the speed restriction. First, you could buy a
LocalTalk PC Card. With it, you can communicate with the printer at 230K
bps, instead of 9600.
Second, you could try this method for changing speeds:
1) Check the version of DOS being used and the upper limit of its serial
port communications.
2) Set the PC communications port to 96, N, 8, 1, P to talk to the
LaserWriter IINTX.
3) Set the LaserWriter DIP switches for serial communications at 9600 baud.
4) Send the PostScript Command to the LaserWriter to set the new faster
communications speed.
5) Reset the PC communications port to the desired speed and parameters
using the DOS MODE Command.
The LaserWriter should now be set for the new speed.
Note: It is important to set the handshaking in the LaserWriter to
DTR/DSR for DOS if you are not using XON/XOFF. The LaserWriter's default
is XON/XOFF, and DOS defaults to DTR/DSR.