>I'm not sure why you are "talking" to the printer this way (using the FOPEN() function), however, if this is how you need to communicate with the printer, the problem may be with you "calling" LPT1.DOS instead of PRN. If I am correct (and I'm just guessing) LPT1.DOS is not a direct call to the printer port - it only "represents" the port to the OS. Check it out...

Several reasons may be entering the picture - the lpt1.dos device may not be defined, may require a different reference under the operating system version, and still doesn't bypass the spooler to talk directly to the port - Windows will stand between the app and the hardware.

PRN is not defined by default under NT IAC, and would require the use of a trailing : if it were a known device.