scope:

This standard establishes requirements and test procedures for voltage ranges and characteristics (i.e., transients and noise) associated with the input voltage of network telecommunications equipment powered from dc power systems in the telecommunications environment. This standard does not:

• Specify dc power plant voltage levels.

• Specify the voltage applied to the interface between the network and customer installations (i.e., network span voltages or voltages at the customer interface).

• Apply to equipment intended to be powered from the telecommunications span.

Purpose

The purpose of this standard is to specify:

• The steady-state dc input voltage ranges over which telecommunications load equipment (TLE) is required to operate when connected to the nominal voltage power plants addressed in this standard;

• Transient voltage tolerance requirements for TLE;

• Noise immunity for TLE;

• Limits for noise returned by the TLE;

• Voltage levels for uniform Mean-Time-Between-Failure (MTBF) calculations;

• Undervoltage requirements;

• Overvoltage requirements;

• Test procedures;

• Personnel hazards; and

• Marking.

This standard is intended to be applied to equipment designed and manufactured after the effective issue date of this standard. Nothing in this standard should be interpreted to require the retrofitting of existing TLE or power plants. This standard does not restrict the development or use of telecommunications architectures that use other voltage levels and ranges.