Power Supply Unit Load Requirements; Unit Load Calculation Rules - Lucent Technologies MERLIN LEGEND Release 5.0 Pocket Reference

Power Supply Unit Load Requirements

Unit Load Calculation Rules

Mode
Hybrid/PBX,
Modified Key,
or
Behind Switch
Square Key
or
Behind Switch
*
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 54 and auxiliary
power may be required:
Only MLX or analog multiline station modules are installed.
More than 45 MLX-20L or 34-button analog multiline telephones are
installed.
The 391A3 power supply has a maximum rating of 75 unit loads. Use
this power supply in place of a 391A1 or 391A2 on systems where unit
loads will exceed 54.
Auxiliary Power Units cannot be used with the 391A3 power supply.
†
The 391A1 power supply unit generally supports 4 modules of any type
in Square Key mode.
82
Installed
Modules
*
6
4 or fewer †
Calculation
Not required
Not required