a first amplifier configured for amplifying {HEAD ~ the data} received from {TAIL ~ the first I/O port} and outputting the amplified data to the second I/O port; and 
a first amplifier configured for amplifying { HEAD ~ the data } received from { TAIL ~ the first I / O port } and outputting the amplified data to the second I / O port ; and
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH