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Functional Description 150-451-103-02, Revision 02
8 September 18, 1998 HDU-451 List 3
Table 4. The Features of the HDU-451 Front Panel
Feature Function
+/- V Jacks These two test jacks enable you to monitor the input voltage feed on
the HDSL line. Typical values range from 130V to 200V, based on
the distance from the HLU or first HDU-451.
Loopback LED Shows the current loopback status. The LED has the following
states:
• Green indicates loopback NDU1 or NDU2 is active.
• Yellow indicates loopback CDU1 or CDU2 is active.
•
Flashing Yellow indicates the doubler is in an armed state ready
to accept a 16-bit intelligent loopback command issued at the
HLU or HRU DS1 inputs.
HDSL IN LEDs Two LEDs indicate the status of the two HDSL input line pairs: HDSL
IN 1 and HDSL IN 2. These indicators have the following states:
Flashing Green indicates synchronization is being attempted with
the HLU.
Green indicates HDSL frame synchronization between the HLU and
HDSL input.
Flashing Red indicates an HDSL error
Yellow indicates a Margin alarm at this HDSL port.
HDSL OUT LEDs Two LEDs indicate the status of the two HDSL output line pairs:
HDSL OUT 1 and HDSL OUT 2. These indicators have the following
states:
Flashing Green indicates synchronization is being attempted with
the HRU or a second HDU-451.
Green indicates HDSL frame synchronization between the HDSL
output and the HRU or a second HDU-451.
Flashing Red indicates an HDSL Error.
Yellow indicates a Margin alarm at this HDSL port.
Craft (RS-232) port Provides bidirectional communication between the unit and an
external terminal to allow performance monitoring through the
maintenance terminal screens.