Issue 5 November 2000
363-206-208
Equipment and Front Access Cable Installation for the DDM-2000 OC-12 Multiplexer
Lucent Technologies - Proprietary
See Notice on first page
NOTE:
The front access interbay power cables are installed in the same manner as the
rear access power cables, except that the Group 150 shelf power cable has been
routed to the front of the shelf. This is also true for the Group 148 fan shelf power
cable.
Office Alarm Cabling - Front Access
Description
NOTE:
This procedure should be performed if specified in the order.
Office alarms are the common method 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, this is the bottom shelf position, referred to as shelf 1. If the bottom shelf
position (shelf 1) is unequipped 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, perform
“Intershelf Office Alarm Cabling Procedure”.
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 24 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, then 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-12 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 3-6 on page 3-38.
Office alarm connections are listed in Table 3-7 on page 3-39.
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