There are three tabs;
Analysis
Pointers keep SONET signals synchronous by compensating for timing differences without having to use stuffing bits. Pointers are
allowed to move up or down every three frames however the actual rate should be slower. The Administrative Unit (AU) and the
Tributary Unit (TU) each has its own pointer and the unit has two tabs for displaying the values and measurements.
o
For STS pointers:
- SS bits – displays bits 5 and 6 of the H1 byte to indicate SONET [10], SONET [00], Unknown [01] and [11] signal
type
- Pointer value – displays the H1 and H2 values (addresses) indicating the offset in bytes between the pointer and
first byte of the STS-n
- LOP (Loss of Pointer)
- PJE and NJE
- NDF or New Data Flags. NDF is enabled when at least 3 out 4 bits match “1001” and is disabled when 3 out of
bits match “0110”
- Difference and Sum
o
For TV pointers:
- Pointer value
- LOP (Loss of Pointer)
- PJE and NJE
- NDF or New Data Flags
- Difference and Sum
TX150 e-Manual D07-00-023 Rev A02
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