function unCheckAll() {
 // if one Pallet Labeling System is unchecked, uncheck "All Pallet Labeling Systems"
 if(document.forms.EmailData.SA1000.checked == false || 
    document.forms.EmailData.SA1010.checked == false || 
    document.forms.EmailData.SA2200.checked == false || 
    document.forms.EmailData.SA2210.checked == false)
 {
  document.forms.EmailData.AllPalletLabelingSystems.checked = false;
 }
 // if one Unit Load Stacker is unchecked, uncheck "All Unit Load Stackers"
 if(document.forms.EmailData.PS520.checked == false ||
    document.forms.EmailData.PS600.checked == false)
 {
  document.forms.EmailData.AllUnitLoadStackers.checked = false;
 }
 // if one RFID Equipment is unchecked, uncheck "All RFID Equipment"
 if(document.forms.EmailData.RFIDPortal.checked == false || 
    document.forms.EmailData.RFIDCaseReader.checked == false || 
    document.forms.EmailData.RFIDCaseLabeler.checked == false)
 {
  document.forms.EmailData.AllRFIDEquipment.checked = false;
 }
}