363-206-305
Operations Interfaces
Issue 3 June 2000
6-13
ACTIVE Indicators
6
A green ACTIVE indicator is provided on each OLIU circuit pack. It indicates which
circuit packs are active (carrying service) at any given time. Since both OLIUs are
active in a ring configuration, both ACTIVE indicators will always be illuminated.
Although there is no ACTIVE LED on each low-speed circuit pack to indicate it is
carrying service, the status of the circuit packs can normally be deduced without
the CIT. If a service DS1 circuit pack FAULT LED is illuminated and the DS1
protection circuit pack FAULT LED is not illuminated, then the protection circuit
pack is carrying service and the failed circuit pack can be removed. The exception
to this rule is if a manual protection switch has been executed. In this case, the
ABN LED on the user panel will be illuminated and the user will have to use a CIT
to check the status of the system.
Office Alarms
6
The DDM-2000 FiberReach Multiplexer provides relay contacts for wiring to the
office audible and visual alarms. The following contacts are provided for each
alarm condition:
â–
CR (critical)
â–
MJ (major)
â–
MN (minor).
The MJ and CR contact closures are designed to allow these office alarms to be
ORed together and reported as an office MJ alarm.
The CR alarms are fail-safed against power failures. They are activated even if the
shelf loses both power feeders.
The audible office alarms for a given site are silenced through activation of the
ACO function. Visual alarms are not extinguished by the ACO function.
An alarm hold-off delay is provided, to prevent transient failures from causing
unnecessary maintenance activity. The office alarms will not be activated unless a
condition of greater duration than the alarm hold-off delay occurs. When a failure
clears, an alarm clear delay prevents premature clearing of the alarm.
As with the user panel indicators, when multiple alarms are active, the highest
level office alarm (audible and visual) is activated. When the highest level alarm
clears, the office alarm "bumps down" to the next highest level active alarm.
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