100:	mov dx, 378	; write to LPT1
	out dx, al
	ret

200:	mov cx, ff	; main
203:	mov al, cl
	call 100	; write to LPT1
	call 400	; delay
20B:	loop 203
20D:	ret

300:	push cx
	mov cx,ffff
304:	loop 304
	pop cx
	ret

400:	push cx		; delay
	mov cx,400
404:	call 300
407:	loop 404
	pop cx
	ret

500:	mov dx, 379	: read from LPT1
	in al, dx
	mov bl, 77
	cmp al, bl
	jnz 500
50A:	call 200
50D:

703:	mov ah,7	; getchar
	int 21
	mov dx,378
	out dx,al
	mov bl,1B	: ESC
	cmp al,bl
	jz 713
711:	jmp 703		; while ( !ESC ) { LPT1 <- getchar(); }
713:

-g=200 20D 	(P4, 1600 MHz ~15 sec)
-g=500 50A	(prog is waiting while switch1 will be on)
-g=500 50D
-g=703 713