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MERLIN LEGEND Communications System Release 7.0
Pocket Reference
555-670-116
Issue 1
April 1999
90
Power Supply Unit Load Requirements
Power Supply Unit Load Requirements
Unit Load Calculation Rules
Mode
Installed
Modules Calculation
Hybrid/PBX,
Modified Key,
or
Behind Switch
6
1
1 The 391A1 and 391A2 power supply units generally support 6 modules
of any type in Hybrid/PBX mode. However, if all 6 carrier slots meet the
following conditions, the unit load total may exceed 48:
Only MLX or analog multiline station modules are installed.
More than 45 MLX-20L or 34-button analog multiline telephones are
installed.
The 391C1 and 391A3 power supplies have maximum ratings of 96 and 72
unit loads respectively. Use these power supplies in place of a 391A1 or
391A2 on systems where unit loads will exceed 48.
Not required.
Square Key
or
Behind Switch
4 or fewer
2
2 The 391A1 power supply unit generally supports 4 modules of any type in
Square Key mode.
Not required.
Square Key
or
Behind Switch
5 or more Use the “Unit Load Rating of System
Modules” table and instructions below to
determine the estimated unit loads (ULs):
■ If the ULs < 96 and the 391C1power
supply is used, or the ULs < 72 and the
391A3 power supply is used, then no
calculation is required. If a 391A1 or
391A2 power supply is used and the
ULs > 48, then replace the power
supply with a 391C1 power supply.
■ If ULs > 96, reconfigure the system so
that the total ULs does not exceed 96
per carrier.
For more information on unit load
calculation, refer to Appendix F of
System
Planning
.