I am migrating an old 16 bit windows app. thas does direct serial port handling in order to take full advantage of a specialized printer. I have already programmed an interface using Win32 apis that takes care of this.
There is also a DOS application, running on a DOS window, that prints thru the system printer, which happens to be the same serial printer. So, it requires the printer driver to be installed.
It is mandatory to have both applications running on the same machine.
The problem is that whenever the driver is installed, the port seems to be unavailable for my interface, which gets an "invalid_operation" return code for all of its api requests. As soon as I remove the printer driver from the system, my interface works OK.
So far I have tried to set the serial port as a multiport and as a regular port, but the problem remains the same.
The question is what more settings can I try to fix the problem, or if there is any other printer driver that doesn´t block the port
Here is some specific information:
old environment: Pentium I w/Windows 95
new environment: Pentium IV w/Windows 2000
serial printer: Epson TM - H5000