For example, the client with his communications system is traveling by {HEAD ~ train} and can listen to {TAIL ~ music} 
For example , the client with his communications system is traveling by { HEAD ~ train } and can listen to { TAIL ~ music }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL