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