function submitchk(f)
{
	var v=new Array(f.sip_co1.selectedIndex,
			f.sip_co2.selectedIndex,
			f.sip_co3.selectedIndex,
			f.sip_co4.selectedIndex,
			f.sip_co5.selectedIndex,
			f.sip_co6.selectedIndex,
			f.sip_co7.selectedIndex);
			
	var i, j;

	for (i=0; i<7; i++) {
		for (j=i+1; j<7; j++) {
			// we use voice_codec_pri9 to find the string of selectedindex for pri1..9
			// as list pri1..9 have save menu options
			if (v[i]==v[j] && f.sip_co7[v[i]].value!='none') {
				alert("Codec Priority "+(i+1)+" and "+(j+1)+" should not be the same");
				return(false);
			}
		}
	}

	/*if (	!value_between(f.voice_rtp_timeout.value, 1, 100, "RTP Timeout should be between 1..100.") ||
		!value_between(f.voice_rtp_packet_lost_percent.value, 0, 100, "RTP Packet Lost Percentage should be between 1..100.") ||
		!value_between(f.voice_max_icmp_unreachable.value, 0, 1000, "Maximum ICMP unreachable should be between 1..1000.") ) {
		return false;
	}*/
	
	return true;
}