Also, {HEAD ~ the bridging and signaling unit} responds by beginning {TAIL ~ its next mode} of operation, e.g., playing so called music on hold to the caller, which is done while waiting for receipt of the called partys return telephone call 
responds by beginning
Also , { HEAD ~ the bridging and signaling unit } responds by beginning { TAIL ~ its next mode } of operation , e.g. , playing so called music on hold to the caller , which is done while waiting for receipt of the called partys return telephone call
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL 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 OTH OTH OTH OTH OTH