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