The adapter then goes on hook , terminating {HEAD ~ the call} to {TAIL ~ the PBX} 
to
The adapter then goes on hook , terminating { HEAD ~ the call } to { TAIL ~ the PBX }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL