The increasing need for protection of telecommunication equipment against overcurrents and overvoltages has resulted in the development of a number of new protective components and elements. The purpose of this Recommendation is to provide information about the application of new devices in the different parts of a telecommunication network. It is intended to guide protection engineers and manufacturers of equipment to select appropriate protection devices for a telecommunication system. It should be noted that the implementation of protective devices in a communication system is only one of several methods to mitigate transient overvoltages. By using an efficient shielding and bonding technique the need of protective components may be significantly reduced.