363-206-305
Circuit Pack Descriptions
Issue 3 June 2000
7-93
power). The PSU converts incoming 60V AC to -48V DC for use by the Wideband
and Narrowband shelves. In applications where -48V DC is readily available, The
PSU is not required.
PCU Faceplate Controls and Indicators
7
The PCU circuit pack faceplate controls and indicators are shown in Figure 7-37.
Figure 7-37. AUA432 PCU Circuit Pack
CDTU Circuit Pack Description
7
The Channel and Drop Test Unit (CDTU) circuit pack provides the remote end
terminations and detectors required to support end-to-end channel testing of two-
wire locally-switched services, such as POTS, coin, and multiparty services.
When a channel unit test request is received on the Narrowband shelf, the
DSXBIU instructs the channel unit associated with the channel under test to
operate its test relay. The DSXBIU then instructs the CDTU that a test is
occurring, and the CDTU then performs a drop test and reports the results back to
the DSXBIU. The CDTU provides channel test terminations in sequence based on
results from the channel test detectors and instructions from the DSXBIU.
■
Hazardous voltage
■
Foreign voltage
■
Metallic leakage
■
Receiver off-hook
■
Lack of continuity to the station set.
The circuit pack contains a red fail LED to indicate an internal failure in the CDTU
circuit pack and a green busy LED to indicate that a test session is active.
PCU
-48VDC
FAIL
Lucent
SLC-2000
AUA432
-48VDC
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