Check the listing for details. Z-BLOCKER Z 1E-ZA431PJ3X-A ALARM PANEL DSL FILTER. Color: Black, Condition: Open box. Listed at 9.00 USD. The Z-A431PJ31X-A is an Alarm Panel DSL Filter designed to allow to co-existence of DSL service in homes where security systems are installed. The Excelsus Alarm Panel DSL Filter isolates high-freqency DSL signals from low-frequency voice and data communicationCompatibility with most major alarm panelsAllows reliable alarm panel reporting and cut-line protectionUninterrupted DSL communication during alarm panel line seizure and incident reportingRJ31X-RJ38X connections for line seizure and cut-line protectionOver-voltage protection, protecting alarm panel from power surgesEasy installation for service provider personnel less than 15 minutes to insert filter between alarm panel and phone line and perform a system testCompliant and listed with FCC Part 68, CS-03, UL 60950 and CSA 22.2 60950