Unit Load Rules; Calculating Unit Loads - Lucent Technologies MERLIN LEGEND Release 5.0 System Planning Manual

MERLIN LEGEND Communications System Release 5.0
System Planning 555-650-112
F Unit Load Calculation

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 in various 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 with-
out exceeding the 54-unit maximum. If, however, both of the following conditions are
true, the unit loads on a carrier can exceed the 54-unit maximum:
All six carrier slots are occupied by MLX or analog multiline telephone mod-
ules
The carrier has a total of more than 45 MLX-20L telephones or 34-button an-
alog multiline telephones installed
The 391A3 power supply has a maximum rating of 75 unit loads. If your system con-
tains a 391A1 or 391A2 power supply module, and the unit loads for that carrier will
exceed 54, a 391A3 power supply should be installed in the system. Auxiliary Power
Units cannot be used with the 391A3 power supply.
Unit Loads for Key or Behind Switch Mode
In a Key or Behind Switch system with four or fewer modules, no calculation is need-
ed. 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.
Issue 1
June 1997
Page F-2