FILE MSPSPD.HLP SERIAL PRINTER DRIVER September 1991 MSPSPD.ASM is a public domain serial printer driver for MS-DOS computers, written by Frank Whaley in 1989 and found by Joe Doupnik in the mirror/printer directory on wuarchive.wustl.edu. The original name of the program was XONXOFF; it has been renamed to MSPSPD to fit the Kermit Distribution naming conventions. MS-DOS allows you to define a COM port as a printer device using the MODE command, for use with a serial printer, for example: MODE COM1:9600,N,8,1,P MODE LPT1:=COM1 However, MS-DOS does not provide flow control between itself and a serial printer. MS-DOS Kermit uses standard DOS calls for printer operations (print screen, transparent print, autoprint, etc). A common complaint is that these print operations do not work well with serial printers -- characters are lost or garbled, etc. The MSPSPD program provides the needed flow control for serial printers. It works only for COM1 only. It installs itself as a terminate-and-stay-resident (TSR) program, intercepts DOS interrupt 17H, leaves the port baud rate and other parameters as found (so you must set them with the MODE command), and contains no provisions for de-installation. The program is written in assembly language. To build it: MASM MSPSPD; LINK MSPSPD; DEL MSPSPD.OBJ EXE2BIN MSPSPD.EXE MSPSPD.COM DEL MSPSPD.EXE Then run it from your AUTOEXEC.BAT file after giving the necessary MODE commands, for example: MODE COM1:9600,N,8,1,P MODE LPT1:=COM1 C:\MSPSPD For generality, this program needs to be modified to accept command line arguments to specify which port address (and IRQ) to use, and to allow deinstallation. The normal port values are: Port Address IRQ COM1 03F8H 4 COM2 02F8H 3 COM3 03220 3 (PS/2) COM4 03228 3 (PS/2) NOTE: Non-PS/2s probably use different addresses and IRQs for COM3 and COM4. If you make these modifications, be sure to send the improved program back to Kermit Distribution at Columbia University so everybody can benefit from your work. [End of MSPSPD.HLP]