EXFO FTB-8510B Guia Del Usuario página 885

The Overwrite LED indicates if there is any byte in any timeslot having
the Overwrite check box selected (LED is green) or not (LED is gray).
Disable All allows to clear the Overwrite check box for all bytes in all
timeslots.
The following overhead byte values are displayed in hexadecimal format.
However, a common field allows to see the value of specific byte in binary
format. Click on the blue label of a byte and its binary value will be
displayed in the common field beside the Timeslot selection.
H1 and H2: Pointer
H3: Pointer Action
B2: BIP-8
K1 and K2: Automatic Protection Switching (APS)
D4 through D12: Data Communications Channel (DCC)
S1/Z1
S1: Synchronization Status (STS-1 #1 of an electrical or OC-N signal)
Z1: Growth (STS-1 #2, STS-1 #3, up to STS-1 #N of a OC-N (N>3)
signal)
M0 or M1/Z2
M0: REI-L (STS-1 #1 of an STS-1e signal; STS-1 #4 of OC-192/OC-768
signal)
M1: REI-L (STS-1 #3 of STS-3e or OC-3 signal; STS-1 #7 of an
OC-12/OC-48/OC-192/OC-768 signal)
Z2: Growth (STS-1 #1 up to STS-1 #48 except for timeslots used by M0
and M1).
Undefined "--" for all other timeslots not covered by M0, M1, and Z2.
E2: Orderwire
SONET/SDH Application
SONET Tabs
Line OH TX/RX (SONET)
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