AT&T Release 2.0 manual Checking Unit Loads, Unit Loads for the Hvbrid/PBX Mode

Installing the Control Unit

Unit Loads

A unit load is a measure of power (1.9 watts) used to determine the electrical load that the following components have on each carrier’s power supply:

■telephones and adjuncts

Only the telephones and adjuncts that connect to the analog and digital ports on the control unit require unit load calculation. Do not include any equipment with its own power supply in the unit load calculation.

■800 DID modules

Checking Unit Loads

In the event of maintenance or equipment changes, recalculate the unit loads for each carrier resulting in a different configuration.

Use the worksheet in Appendix B.

General Rule: If you can distribute the 800 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. The next two sections provide the rules for calculating unit loads in various modes.

Unit Loads for the Hvbrid/PBX Mode

The power supply (model 391A1) generally supports six modules of any type in a Hybrid/PBX system— without requiring an auxiliary power unit.

If, however, both of the following conditions are true, the unit loads on a carrier can exceed the 54-unit maximum, and therefore require auxiliary power:

■all six carrier slots are occupied by MLX telephone or analog multiline telephone modules

2-18Unit Loads