{TAIL ~ The plug board} may provide a rib in {HEAD ~ both top and back surfaces} thereof, while the upper and lower housings each provides a groove to receive the rib in the plug board 
{ TAIL ~ The plug board } may provide a rib in { HEAD ~ both top and back surfaces } thereof , while the upper and lower housings each provides a groove to receive the rib in the plug board
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD 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