US Patent 7265646 Tamper-resistant filter

Method and apparatus for protecting a filter trap that is utilized in a coaxial cable system against theft of service. A barrier is mounted inside a filter housing which includes a pair of end connectors that are aligned along a common axis. The barrier is mounted on one or both end faces plate or isolation shield for intercepting a cutting tool moving along the axis to direct the tool away from the axis. At least one opening in the plate adjacent to the barrier engages the intercepted cutting tool and further directs the tool away from the axis causing the tool to break or to prevent the formation of a passage between the end connectors.