下面这个C语言程序运行后可以发出声音，但是插上耳机后用耳机听却没有声音，请高手帮一下解决这个问题。
#include <stdio.h>
#include <dos.h>
#include <graphics.h>
#include <conio.h>
#include <stdlib.h>
#define INTR 0x1c

void interrupt ( *oldhandler) ();
int fre[]={523,659,587,659,587,494,587,523,440,440,440,330,392,440,494,494,330,415,494,523,523,523};

void interrupt handler(){
unsigned i;
static int flag;
static int k=0;
union{
long divisor;
unsigned char c[2];
}music;
unsigned char port;
flag++;
if (flag>=4){
flag=0;
music.divisor=1190000/fre[k];
outportb(67,182);
outportb(66,music.c[0]);
outportb(66,music.c[1]);
port=inportb(97);
outport(97,port|3);
k++;
if(k>=22) k=1;
}
oldhandler();
}

int main(void)
{
int gdriver=DETECT,gmode,errorcode;
int midx,midy,i;
oldhandler=getvect(INTR);
setvect(INTR,handler);
registerbgidriver( EGAVGA_driver );
initgraph(&gdriver,&gmode,"e:\\tc\\bgi");
errorcode=graphresult();
if(errorcode!=grOk)
{
printf("graphic error:%s\n",grapherrormsg(errorcode));
printf("press any key to halt");
getch();
exit(1);
}
midx=getmaxx()/2;
midy=getmaxy()/2;
for(i=SOLID_FILL;i<USER_FILL;i++)
{
setfillstyle(i,getmaxcolor());
bar(midx-50,midy-50,midx+50,midy+50);
delay(2000);
}
getch();
closegraph();
setvect(INTR,oldhandler);
nosound();
return(0);
}