Siemens FSPHONE is a hardwired surge protector for telephone, DSL or modem connected electronics in residential and light commercial applications. When installed at your telephone service, our FirstSurge telephone surge protector (FSPHONE) protects against electrical power surges that can enter through the main telephone connection and is equipped with a fail short device to permanently ground the telephone line in the event of a power cross. Every FSPHONE is sized with enough surge current capacity allowing it to take multiple surge hits without wearing out.