This enables an engineer to test a telephone line by simply clipping a crocodile clip onto {TAIL ~ the test contact member} and {HEAD ~ a wall member} 
This enables an engineer to test a telephone line by simply clipping a crocodile clip onto { TAIL ~ the test contact member } and { HEAD ~ a wall member }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD