The RJ-45 and RJ-11 Surge Protection Module for Analog Phone Line from APC is a replacement module for APC's Modular Data Line Surge Protection System. The module installs in an available port on this system to provide RJ-45 or RJ-11 analog phone line surge protection. This is a great way to replace a failed module or to add another line of RJ-45 or RJ-11 protection to the system.