ASR 5500 User manual

SSC Alarm Cabling
This chapter describes how to cable the alarm contacts on the System Status Card (SSC).
The CO alarm interface of the SSC is suitable for connection to intra-building or unexposed wiring or
cabling only. This interface MUST NOT be metallically connected to interfaces that connect to the outside
plant (OSP) or its wiring. This interface is designed for use as an intra-building interface only (Type 2 or
Type 4 ports as described in GR-1089-CORE, Issue 5) and requires isolation from the exposed OSP
cabling. The addition of Primary Protectors is not sufficient protection in order to connect these interfaces
metallically to OSP wiring.
Caution
It includes the following sections:
•CO Alarm Interface, page 1
•Alarm Cutoff (ACO), page 2
•Alarm Connector Pinout, page 3
•Electrical Characteristics, page 3
•CO Alarm Wiring Example, page 4
CO Alarm Interface
The Central Office (CO) Alarm interface on the SSC is a DB15 female connector that supports three low
voltage, normally-closed/normally-open dry-contact relays. These Form C relays interface with an CO alarm
monitor panel to trigger external audio and/or visual indicators.
Three alarm levels are supported by the relays:
•Minor Alarm –This alarm is triggered when a high temperature is detected on a card, causing the fan
tray to switch the fans to high speed.
•Major Alarm –This alarm is triggered when there is a:
•Hardware failure that causes the card to be placed in an off-line state
•PFU failure or removal from the chassis
•Failure of one or more fans on any of the upper or lower fan tray units
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•Fan tray failure or any fan tray unit is removed from the chassis
•Critical Alarm –This alarm is triggered when a degradation in service is detected. For example, if the
system is supporting a large number of subscribers and DPCs are removed, the amount of available CPU
and memory resources available for use are reduced.
Alarm Cutoff (ACO)
The front panel of the SSC includes an audible system alarm and an Alarm Cutoff (ACO) switch. Press and
release this switch to reset the system alarm speaker.
Figure 1: SSC CO Alarm Interface
CO alarm interface (DB15)2Connector cover plate1
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SSC Alarm Cabling
Alarm Cutoff (ACO)

Audible alarm4Alarm Cutoff (ACO) switch3
Alarm Connector Pinout
The CO alarm connector pinout is provided in the table below.
Use a Phillips #1 screwdriver to remove the two screws that secure the cover plate over the alarm connector.
Table 1: DB15S CO Alarm Connector Pinout
SignalAlarm LevelPin
Normally OpenMinor1
Normally Closed2
Not connected
—
3
Normally OpenMajor4
Normally Closed5
Not connected
—
6
Normally OpenCritical7
Normally Closed8
Minor, CommonMinor9
Not connected
—
10
Not connected
—
11
Major, CommonMajor12
Not connected
—
13
Not connected
—
14
Critical, CommonCritical15
Electrical Characteristics
Each of the three dry-contact, Form C relay switches is rated to support a maximum switching current of
1A@30VDC.
Never connect a high voltage/high current device such as an audible alarm/siren or incandescent lamp
directly to the EO alarm connector.
Caution
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SSC Alarm Cabling
Alarm Connector Pinout

CO Alarm Wiring Example
The figure below depicts how the three dry-contact (no voltage supplied) relay contacts can each control up
to two alarming devices. In this example the SSC CO alarm interface is connected to a CO Alarm Panel, where
green LEDs are wired to indicate normal operation, and red LEDs are wired to indicate alarm conditions.
With all relays de-energized, the green LEDs are illuminated. If an alarm relay is energized, its NO (normally
open) contact closes; the green LED is extinguished and the red LED is illuminated.
Figure 2: CO Alarm Interface Schematic
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SSC Alarm Cabling
CO Alarm Wiring Example