INT 21 - Attachmate Extra! - SEND KEYSTROKES TO HOST WINDOW AH = A3h AL = window number (1-4=host B-E) CX = 0001h DS:BX -> keystroke buffer DL = zero if keystroke buffer contains host function code (see #01799), non-zero if keystroke buffer contains ASCII character Return: CX = zero if character sent, non-zero if not BX incremented if CX=0