ITU-T Recommendations

Recommendation ITU-T K.45 specifies resistibility requirements and test procedures for telecommunication equipment installed between telecommunication centres and between a telecommunication centre and the customer's premises.
Overvoltages or overcurrents covered by this Recommendation include surges due to lightning on or near the line plant, short-term induction from adjacent AC power lines or railway systems, earth potential rise due to power faults, direct contact between telecommunication lines and power lines and electrostatic discharges.
Changes compared with Recommendation ITU-T K.45 (2018) include:
• A DC insulation resistance test;
• a special requirements annex.
Amendment 1 refers to Annex A, which applies to special environments, particularly primary protection that has a poor earth connection that does not meet the requirements of Recommendation ITU-T K.66. This condition is simulated by increasing the STP earth resistance (R1) from zero to 100. Readers have overlooked this change, possibly because the test circuit diagram is in Recommendation ITU-T K.44.
To alert readers to this a text note has been inserted in the Comments column.