INT 17 - PRINTER - WRITE CHARACTER

	AH = 00h
	AL = character to write
	DX = printer number (00h-02h)
Return: AH = printer status (see #00631)
Note:	Under PhysTechSoft's PTS ROM-DOS the parallel port can also be
	  accessed as COM5.
BUGS:	Some print spoolers trash the BX register on return.
	Some original IBM BIOSes set more than one printer status bits at
	  a time, while only one of them is correct.
SeeAlso: AH=02h,AH=84h"AX",AX=6F02h,AH=F1h,INT 16/AX=FFE3h,INT 1A/AH=11h"NEC"
SeeAlso: INT 4B/AH=00h,PORT 0278h"PRINTER",MEM 0040h:0008h,MEM 0040h:0078h