/* For time delay generation we are using the delay (unsigned milliseconds) function from Borland C/C++ dos.h library. */
	#include <dos.h>
	main()
	{
 	unsigned char orgbits;	/* for orginal status of port B 		*/
	unsigned char bits;	/* new status of port B 		*/ 
 	outp(0x43, 0xB6);	/* 8253/54 control byte 		*/ 
/* For D3 note 1.1931MHz/147Hz=8116 =1FB4 Hex 		*/ 
 	outp(0x42,0xB4);	/* send the low byte to port 0x42 	*/ 
 	outp(0x42,0x1F);	/* send the high byte to port 0x42 	*/
 	orgbits=inp(0x61);	/* get the original status of port B 	*/
 	bits=orgbits|3; 		/* make d0=1,d1=1 to turn the speaker on	*/
 	outp(0x61,bits);		/* speaker is on and note is playing 	*/
 	delay(250);		/* wait for 250 milliseconds 		*/
 	outp(0x61,orgbits);	/* turn the speaker off 			*/
 	delay(100);		/* wait for 100 milliseconds 		*/
/* Repeat for A3 note where 1.1931MHz/220Hz=5423 =152F Hex */ 
 	outp(0x42,0x2F);	/* low byte 				*/	
 	outp(0x42,0x15);	/* high byte 				*/
 	orgbits=inp(0x61);
 	bits=orgbits|3;
 	outp(0x61,bits);
 	delay(500);
 	outp(0x61,orgbits);
 	delay(100);
/* Repeat for A4 note where 1.1931MHz/440Hz=2711=0A97 Hex */ 
 	outp(0x42,0x97);	/* low byte */
 	outp(0x42,0x0A);	/* high byte */
 	orgbits=inp(0x61);
 	bits=orgbits|3;
 	outp(0x61,bits);
 	delay(500);
 	outp(0x61,orgbits);
 	}