INT 15 - CASSETTE - WRITE DATA (PCIBM PC and PCjr only)
	AH = 03h
	CX = number of bytes to write
	ES:BX -> data buffer
Return: CF clear if successful
	    ES:BX -> byte following last byte written
	CF set on error
	AH = status (see #00409)
	CX = 0000h
SeeAlso: AH=00h"CASSETTE",AH=02h"CASSETTE"