What is the RJ31X cord used for in alarm systems?

• A. Transmitting video feed to a monitoring center
• B. Programming the control panel
• C. Connecting to an RJ31X block to the alarm panel using spade connectors
• D. Providing power to the panel

Answer: (C)

Seizing the phone line for alarm signaling. The RJ31X arrangement is a dedicated interface on the home telephone line that lets the alarm panel take control of the line when an alarm occurs, so the monitoring center can receive the signal. The RJ31X cord specifically connects the alarm panel to the RJ31X block on the house’s phone line—using spade connectors on the panel side to hook into the panel’s line terminals—while the other end plugs into the RJ31X block. When an alarm triggers, the panel seizes the line through that block, disconnecting the house phone from the line if needed, and places its call to the monitoring center. This setup is designed for reliable outbound signaling, not for video transmission, programming, or supplying power.