The CMSP-DT-2 is a high performance 3-stage lightning protector that provides superior protection for up to two DSL, Telephone and T1 lines from transients and surges. Failsafe Feature The CMSP-DT-2 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 CMSP-DT-2 features four RJ11 jacks for ease of installation. The rugged aluminum chassis can be wall or shelf mounted. Mounting holes are provided on the unit. This protector is also available in a 4-port version, L-com part number CMSP-DT-4.