This attribute indicates the total number of one second intervals for
which the STS far-end line is unavailable. The STS far-end line
becomes unavailable at the onset of 10 consecutive FELSESs. The
10 FELSESs are included in the unavailable time. Once unavailable,
the STS far-end line becomes available at the onset of 10
contiguous seconds with no FELSES. The 10 seconds with no
FELSES are excluded from the unavailable time. For second
intervals where a Far-End Line Unavailable Second (FELUAS) is
counted, counting of FELCV, FELES, FELSES and FELAISS is
inhibited.