Unit Load Rules; Calculating Unit Loads - Lucent Technologies MERLIN LEGEND Release 6.1 System Planning Manual

MERLIN LEGENDCommunications System Release 6.1
System Planning 555-661-112
F Unit Load Calculation

Unit Load Rules

Unit Load Rules
A general rule to follow is that if you can distribute the DID modules and telephone
modules equally across the carriers, you will prevent unnecessary drain on any
one carrier.
Also, depending on the system's mode, the rules vary. This section provides the
rules for calculating unit loads for the different modes.
Unit Loads for the Hybrid/PBX Mode
The 391A1 and 391A2 power supplies have a maximum rating of 54 unit loads
and generally can support six modules of any type in a system in Hybrid/PBX
mode without exceeding the 54-unit maximum. If, however, both of the
following conditions are true, the unit loads on a carrier might exceed the 54-unit
maximum:
All six carrier slots are occupied by MLX or analog multiline telephone
modules
The carrier has a total of more than 45 MLX-20L telephones or 34-button
analog multiline telephones installed
The 391C1 and 391A3 power supplies have 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, a 391C1 power supply should be installed in the
system.
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 generally supports four modules of any type in Key or
Behind Switch mode.

Calculating Unit Loads

Use the worksheet and instructions in the remainder of this appendix to calculate
unit loads for each carrier. Make a copy of all pages of the worksheet for each
carrier.
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Issue 1
August 1998
Page F-2