DATA COMMUNICATION
Whether directly or indirectly exposed to atmospheric phenomena, conducted and inducted overvoltages pose a thread to telephone lines as much as to any other type of metal-wire based lines
Overvoltages in signal lines
Atmosferic phenomena can also originate conduction and induction of transient overvoltages in telephone networks and lines. A great deal of this type of networks is in fact aerial and thus highly exposed to lightning induction.
In addition to this do atmosferic overvoltages also greatly affect any other type of lines which consist of metallic conductors. The degree of these overvoltages is typically lower than that affecting electrical and telephone lines because these are internal to buildings. it must be acknowledged though, that devices connected to these lines are more sensitive and they do therefore also require efficient surge protection.
Temporary overvoltages will not affect these lines as they do not share the 3-phase distribution system with the neutral wire.
How to protect signal lines against overvoltages
The concept of "signal lines" stands for all those installations which have not been designed to supply electricity to equipments, but to provide transmission of signals (information), i.e. voice, data, etc. The surge protective range is classified into following types of signal lines:
