STS 1 row counter counts pulses of the STS 1 local clock signal and generates a gapped STS 1 enable control signal, which is combined with the AIS/Idle bytecount enable control signal fed back to enable and disable the DS3 AIS/Idle code generation means for mapping DS3 AIS/Idle code bytes in {TAIL ~ the given row} of {HEAD ~ the STS 1 frame} 
STS 1 row counter counts pulses of the STS 1 local clock signal and generates a gapped STS 1 enable control signal , which is combined with the AIS / Idle bytecount enable control signal fed back to enable and disable the DS3 AIS / Idle code generation means for mapping DS3 AIS / Idle code bytes in { TAIL ~ the given row } of { HEAD ~ the STS 1 frame }
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 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 OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD