Lucent Technologies DDM-2000 OC-3, Руководство по установке

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3-14 Issue 9 October 1998
363-206-204
Equipment and Front Access Cable Installation
Office Alarm Cable Installation -
Front Access
Description
NOTE
:
This procedure should be performed if specified in the order.
Office alarms are the common methods used in a central office for maintenance
personnel to quickly isolate a failure to the correct system.
There are two options for cabling office alarms:
■
Cable directly to office alarm equipment
■
Cable to another shelf.
Unless otherwise specified, the lowest shelf in the bay should be cabled directly to
the office alarm equipment as described in "Interbay Alarm Connections".
Typically, the bottom shelf position is referred to as Shelf 1. If the bottom shelf
position (Shelf 1) is unequipped and saved for future growth, leave enough cable
to allow moving the cable down to the bottom position when the shelf is eventually
added.
All the other shelves in the same bay should be part of a daisy chain connecting to
the lowest shelf. For interconnecting other shelves in the bay to the lowest shelf,
follow the instructions under "Intershelf Office Alarm Cabling".
The office alarm relay contacts are rated at 50 VA, which means that they are
capable of switching 1 amp at 50 volts or 2 amps at 25 volts. Their ability to switch
large transient currents means that they can, if necessary, switch up to ten 5-watt
aisle pilot lamps.
If transient voltages or currents are above these limits, transient noise suppressing
devices such as diodes or contact protection networks must be used to keep
within the voltage and current limits. If these protection devices are not sufficient,
an external buffer relay MUST be provided.
In all cases, and as a matter of good practice, suppression devices such as diodes
or contact protection networks must be provided across any external relay coil
being driven by the DDM-2000 OC-3 in order to limit transient voltages and
currents.
Cable options for interconnecting the lowest shelf in the bay to the office alarms
are listed in Table 3-4. Office alarm connections are listed in Table 3-6.
Connection to Office Alarms Procedure
Perform this procedure for the shelf being connected directly to the office alarms.
1. Obtain an office alarm cable Group 439 or 440 (refer to Table 3-4).