HP LaserJet 4 Service Manual - Page 68

Serial MS-DOS Commands Most IBM compatible computers default to a parallel printer port. To ensure that information is sent to your serial printer port, type the following MS-DOS commands at your MS-DOS prompt, or include them in your AUTOEXEC.BAT file. MODE COM1:9600,N,8,1,P MODE LPT1:=COM1 For MS-DOS version 4.0 or above, enter: MODE COM1:9600,N,8,1,B MODE LPT1:=COM1 Note These examples assume that you are using serial printer COM1. If you are using COM2 or COM3, replace COM1 with the the printer port that you are using. Since the MODE command is an external MS-DOS command (a program named MODE.COM is run when the MODE command is invoked), the program file must be contained in the root directory, or in a directory specified in a preceding PATH command in the AUTOEXEC.BAT file. Note After changing the AUTOEXEC.BAT file, reboot the computer to initiate the changes. 3-32 Configuration