The data lines surge protection offers strong protection against transient over-voltages within data lines. Each module will protect two pair of lines in a coordinated manner. Data lines and analogical or digital equipment that are connected, for example computers and PLCs, too are protected. A wide variety of protection modules are available. The data lines should have common and differential protection. The pluggable modules are easily replaceable. The lines do not have to be disconnected in order to change a faulty module. Its radio frequency receptor allows for easier maintenance. When an RF SPD tester is applied and the protector is functional, the LED flickers green. There will be no LED flickering if the cartridge is damaged. The equipment is earthed through a metallic sheet.