If a new customer is using DSL, what might you tell customer?

• A. A DSL filter near or in the panel
• B. A DSL filter must be installed at the service entrance
• C. DSL cannot be used with alarm systems
• D. No filter is necessary for DSL

Answer: (A)

When a customer runs DSL on the same line that the alarm system uses, high‑frequency DSL signals can interfere with the alarm’s signaling. Placing a DSL filter right at the panel or in the panel’s wiring isolates the alarm circuit from the DSL noise, allowing the alarm communicator to operate reliably while still letting DSL function normally on the same line.

Installing a filter at the service entrance is not the targeted solution for the alarm panel itself, and statements that DSL cannot be used with alarm systems or that no filter is necessary are not accurate—filtering is typically required to prevent interference and ensure reliable monitoring.