ADC HiGain HRU-402 Manual page 51

150-402-111-02
The HRU-402 supports four types of loopbacks
•
Network Remote (NREM): the DSX signal is looped back to the DSX at
the HRU.
•
SmartJack (SMJK): loopback at the HRU towards the network initiated
by a 2-in-5 in-band loopback code or out of band ESF facility data link
(FDL) code.
The NREM and SmartJack Loopbacks have two modes of operation as
determined by the SmartJack Alarm Indication Signal (SAIS) user option
settings at the HLU (ENA or DIS). The ENA option causes the HRU to
transmit the Alarm Indication Signal (AIS) towards the CPE. The DIS
option turns off the AIS/CPE signal. To send the AIS pattern to the CPE
during SmartJack or NREM loopbacks, set the SAIS to ENA before the
loopback is initiated.
• Customer Local Loopback (CLOC): signal from CI is looped-back to
customer at HRU-402.
•
Transmit Loss of Signal (TLOS): initiated by a DS-1 LOS condition at
the HRUs DS-1 input port if the TLOS option is enabled. The DSX signal
is looped back logically to the DSX at the HRU.
The HLU supports the following two loopbacks:
•
Network Local Loopback (NLOC): the DSX-1 signal is looped back to
the DSX-1 at the HLU.
•
Customer Remote Loopback (CREM): the signal from the customer is
looped back to the customer at the HLU.
If doublers are used, then the following loopbacks (up to 6 additional) can be
supported:
•
Network Doubler Unit (NDU1 - NDU3) loopbacks. The DSX-1 signal is
looped back to the DSX-1 at the looped doubler.
•
Customer Doubler Unit (CDU1 - CDU3) loopbacks. The signal from the
customer is looped back to the customer at the looped doubler.
HRU-402 List 1A
Initializing the Maintenance Terminal Screens
December 8, 1998
(Figure 18 on page 42).
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