The apparatus 8, wherein {TAIL ~ said alerting means} includes means for transmitting {HEAD ~ a distinguishable audio signal} 
The apparatus 8 , wherein { TAIL ~ said alerting means } includes means for transmitting { HEAD ~ a distinguishable audio signal }
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD