This Handbook provides information on interference measurement techniques on topics covered only in part by Volume IX, Testing methods and measuring apparatus, of the Directives concerning the protection of telecommunication lines against harmful effects from electric power and electrified railway lines, Geneva 1989.

Power and traction lines induce continuous longitudinal currents and voltages to parallel telecommunications lines at fundamental and harmonic frequencies during normal use. On a certain threshold level, these currents or voltages may cause unacceptable transverse interference in telecommunications systems. The intention of this chapter is to discuss measurement methods for determination of this threshold level or testing the immunity of telecommunications systems against induced longitudinal disturbances.

Telecommunications equipment can pose particular difficulties for the EMC engineer. The equipment is frequently large and heavy making it difficult to handle. It may have very large cables connecting it to other telecommunications systems and to the end user. These cable systems are always difficult to effectively simulate during the testing.