The present invention discusses a method and apparatus for selectively providing a power to an alarm system, such as the power source provided by a telephone company, to alarm equipment located at customer's premises in a Fiber to the Premises (FTTP) telephone network. This power source is commonly used to power the POTS lines in a Service Provider's network. Two signals, one relating to the optical connectivity of the network and one relating to the connectivity of virtual circuits, are monitored at the customer premises. A logical operation is performed so as to remove a power source if either of the two signals is lost.