How to Disconnect a Security System From a Phone Line

Open your installation manual, locate the wiring diagram for your system (usually near the end of the book), and find the phone line terminals. This is two terminals on the alarm system circuit board. These are marked phone line, line in or something similar. They are usually toward the right end of the terminal block. Make a note of their terminal numbers or circle them in your manual.

Find your alarm system control box. This is usually located inside the master bedroom closet or laundry room, but in nonstandard installations it could be anywhere within the house.

Open the metal box; you see a circuit board with wires going to it and a battery. On one edge of the circuit board you see a long row of screw terminals. Locate the two terminals for the phone line. That line should lead to a small box with a regular phone cord and connector attached to it; unplug the phone cord and skip to step 5. If you do not see that box, proceed to the next step.

Using a Phillips or regular screwdriver loosen one of the terminals, remove the wire, and wrap it in electrical tape. Disconnect the other wire, and wrap it in electrical tape. Retighten the terminals.

Coil the wire up, put it back inside the box, close the box, and secure the lid.