Data line surges make up an overwhelming majority of all surge induced damages where the equipment was thought to be already protected but had a back door such as a modem line unprotected. Network interface cards, in particular, can be destroyed by relatively mild spikes.

According to Ethernet standards (IEEE 802.3), non-AC network electrical hazards include Direct contact between components and power or lightning circuits, static charge buildup on cables and component, high-energy transients coupled onto the local cabling system (those induced by other cables which are installed in the general proximity of network cables or lightning within a mile radius) and potential differences (even from building to building, between safety grounds to which components are connected.)

• REPLACEABLE, RACKMOUNT, 1U, RS232 SURGE PROTECTION MODULE
• User Manual

• Replaceable surge protection modules
• Data Lines Protected (multi-line only): 1-8
• It protects up to four ports per unit with RJ-45 connector
• Surge Response Time: 1 ns

• The P232R module is for use with RS232 communication equipment (RS232 multiports, asynchronous multiplexers, asynchronous printer spoolers, etc.)