{HEAD ~ An audio speaker} is physically situated near the doorbell switch, for reproducing audio signals from the telephone line which are generated at {TAIL ~ the remote telephone} 
{ HEAD ~ An audio speaker } is physically situated near the doorbell switch , for reproducing audio signals from the telephone line which are generated at { TAIL ~ the remote telephone }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL