The RMSP-DT-12 is a high performance 3-stage lightning protector that provides superior protection for up to 12 DSL, Telephone and T1 lines from transients and surges. Failsafe Feature. The RMSP-DT-12 is designed to convert into a failsafe mode in the rare case of a catastrophic surge or lightning event. For this mode, the resistors in the second stage will fuse and portions of the diode array will short. This effectively disconnects the line from sensitive equipment thus limiting damage. The individual protector modules are field replaceable. The RMSP-DT-12 features 24 RJ11 jacks for ease of installation. The 2U rack panel features a clean, system wide mounting of the circuit protectors and may be installed in the rear of the 19 inch rack where they are normally required for line in and out. For additional information and complete specifications, see data sheet below. This protector is also available in a 4-line rack mount version, see RMSP-DT-4.