Lucent Technologies MERLIN LEGEND Release 5.0 Maintenance And Troubleshooting Manual page 49

MERLIN LEGEND Communications System Release 5.0
Maintenance and Troubleshooting 555-650-140
Introduction
Unit Loads
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 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 be
installed in the system. Auxiliary Power Units cannot be used with the 391A3
power supply.
!
CAUTION:
Running the system with more than 54 unit loads (102.6 watts) per
carrier may not appear to do harm. However, this can cause the
system to malfunction, creating "No Trouble Found" conditions.
If a new power supply is required, complete installation instructions
are provided in Installation.
Issue 1
June 1997
Page 1-31