APC ProtectNet standalone surge protector for Serial RS232 lines (9 pin male to female)
Advanced Surge Protection Against Damaging Power Transients Traveling Over Computer, AV and Network Data Lines

Catastrophic Event Protection
SurgeArrest components such as MOVs and Thermal fuse ensure instantaneous reaction to lightning strikes and wiring faults. If the surge components are damaged due to power spike or over voltage, excess power cannot reach your equipment. Unlike the APC SurgeArrest products, most surge suppressors continue to let power through even after circuits have been damaged, leaving your equipment exposed to other damaging surges.

Data-line Protection
Protection of data lines (Ethernet, Coaxial and Phone lines) ensures complete protection of your equipment from surges. It is very important to protect your equipment from “back door” electric surges traveling through data lines, as they can be as damaging to your equipment as surges traveling over power lines.

Lightning and Surge Protection
To prevent damage to your equipment from electric power surges and spikes.

Fail Safe Mode
Most other surge suppressors continue to let power through even after their circuits have been damaged, leaving your equipment exposed to future surges. APC's SurgeArrest fail safe, which means that once the circuit of an APC SurgeArrest has been compromised the unit disconnects equipment from the power supply ensuring that no damaging surges reach your equipment.