DS3 AIS/Idle code generation means generates {TAIL ~ DS3 AIS/Idle code bytes} in {HEAD ~ response} to the local STS 1 clock signal 
DS3 AIS / Idle code generation means generates { TAIL ~ DS3 AIS / Idle code bytes } in { HEAD ~ response } to the local STS 1 clock signal
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH