Nortel DMS-100 Series Maintenance Manual page 29

The two acceptable limits for transhybrid loss (THL) that depend on the
selected D/A level appear in the following two tables. The NT6X21AD uses
the same diagnostics as the NT6X21AC. The THL limits are modified for
diagnostics purposes. The first table is for the NT6X21AC line card, the
next table is for the NT6X21AD line card.
NT6X21AC THL Limits
Frequency
Minimum
Maximum
NT6X21AD THL Limits
Frequency
Minimum
Maximum
The two limits are required so the system software can determine the
selected digital to analog (D/A) gain on the line card. The system software
compares THL test results against the two possible limits.
Refer to the following figure for a functional block diagram of the RLCM
LCA shelves. This chapter describes the components in this figure.
304 704
–6.2 –6.2
+1.3 +0.8
304 704
–2.7 –2.7
+4.8 +4.3
Data line card (DLC) (NT6X71AA, AB, AC). Provides data
transmission interfaces for operation with computer terminals.
Integrated bit error rate test (IBERT) line card (NT6X99AA). The
IBERT line card provides bit error rate performance (BERP). The line
card tests transmission paths to assess bit error performance of RLCM
hardware components.
DMS-100 Family RLCM Maintenance Manual XPM12 and up
Maintenance overview 1-13
1505 3204
–6.2 –7.2
+0.8 +0.7
1505 3204
–2.7 –3.7
+4.3 +4.2