Unlike power line surges, neither cable, data, nor telephone line surges are generated inside the building. They are only externally generated so the best place to stop these types of surges is where they enter the building. Proper grounding at the service entrance by the service provider is key. Putting cable, data, and telephone line surge protection at the point of use is counterproductive as it provides a path inside and causes ground line contamination when it diverts the surge.
MOV based surge protectors that have data protection are there to protect your devices from the MOV itself as an MOV will send energy to the ground line. The ground line is shared with communication lines.
