VeEX UX400, User Manual

Page: 181 / 209

Overhead Generator
Programming most overhead bytes is possible using the OH Generator feature, however dedicated
test functions are available for Pointer Tasks, Payload Labels, Trace Identifier, APS Testing, TCM
testing.
In some instances, more advanced editing is possible using the dedicated functions.
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7.5.3 Pointer Tasks
Tap the Pointer Tasks icon to display the Pointer testing screens.
7.5.3.1 Pointer Analysis
Pointers keep SDH 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.
For AU pointers:
SS bits – Displays bits 5 and 6 of the H1 byte to indicate SDH [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 AU-n
LOP (Loss of Pointer)
PJE and NJE
NDF or New Data Flag. NDF is enabled when all bits match “1001” (or "0001", "1101", "1011" and "1000") and is disabled when all bits match "0110" (or
"1110", "0010", "0100", "0111").
Difference and Sum
Analysis - AU
UX400 10G e-Manual D07-00-058P RevA00 Page 181 of 209