{HEAD ~ The adapter} also monitors {TAIL ~ the tone cadences} returned to the calling party on the DID trunk or E&M tie line to determine if the called extension is busy or ringing  
monitors
{ HEAD ~ The adapter } also monitors { TAIL ~ the tone cadences } returned to the calling party on the DID trunk or E&M tie line to determine if the called extension is busy or ringing
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH