If answer is detected, the adapter monitors for {TAIL ~ call termination} and the initiation of {HEAD ~ a new call} 
If answer is detected , the adapter monitors for { TAIL ~ call termination } and the initiation of { HEAD ~ a new call }
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD