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