Q: How I can use USB like modern printers within my DOS based applications ?
A: Easiest way for this is dosprint. Most of xBase programmers uses this method: there is a program name dosprint or dosprn.
Download this prg, run before your program and that is all, no modification required on your programs.
This program intercept data sent to printer by your program, convert it to required format and send to USB or anything else modern printers.
Ask Google, select one ( some are free, some aren’t ), download and use.