Lucent Technologies MERLIN LEGEND Release 6.1 Maintenance And Troubleshooting Manual page 62

MERLIN LEGEND Communications System Release 6.1
Maintenance and Troubleshooting 555-661-140
Unit Loads
Checking Unit Loads
In the event of maintenance or equipment changes, recalculate the unit loads
for each carrier where there is a different configuration. Use the worksheet in
Appendix C, "Unit Load Calculation Worksheet."
Generally, if you can distribute the DID modules and telephone modules equally
across the carriers, you prevent unnecessary drain on any one carrier.
The rules vary, however, depending on the system's mode. The next two
sections provide the rules for calculating unit loads in various modes.
Unit Loads for Hybrid/PBX Mode
The power supply (model 391A1) generally supports six modules of any type in
a Hybrid/PBX system. However, if both of the following conditions are true, the
unit loads on a carrier can exceed the 54-unit (102.6-watts) maximum:
All six carrier slots are occupied by MLX telephone or analog multiline
telephone modules.
The carrier has more than 45 MLX-20L telephones and/or 34-button
analog multiline telephones installed.
Unit Loads for Key or Behind Switch Mode
In a Key or Behind Switch system with four or fewer modules, no calculation is
needed. The power supply (model 391A1) generally supports four modules of
any type in Key or Behind Switch mode.
Upgrading the Power Supply
The 391C1 or 391A3 power supply has a maximum rating of 75 unit loads. If
your system contains a 391A1 or 391A2 power supply module, and the unit
loads for that carrier will exceed 54, it is recommended that a 391A3 power
supply or later be installed in the system. Auxiliary Power Units are no longer
necessary.
Issue 1
August 1998
Page 1-36