INT 21 - DOS 1+ - WRITE CHARACTER TO PRINTER
AH = 05h
DL = character to print
Notes:  keyboard checked for ^C/^Break, and INT 23 executed if detected
STDPRN is usually the first parallel port, but may be redirected under
DOS 2+
if the printer is busy, this function will wait

See also: 1700

2105 - DOS 1+ - WRITE CHARACTER TO PRINTER