Parental controls for entertainment digital media are provided that allow a parent to restrict multiple user’s access to entertainment content. The system and method achieve seamless and smooth switch when an agent is temporarily off the seat, implement switch of an agent service call, meet the disaster recovery requirement of an audio channel of the agent service and realize agent service continuity, and meet the construction and maintenance requirement of a customer for low system investment and easy operation. A trap box defines a plenum and is mounted on the canister and a canister pipe stub permits the plenum to communicate with the carbon charge. The spring end-piece constitutes a part that is rigidly attached to one of the two plates prior to the Bourdon tube being soldered to the spring end-piece and that is separated from this plate once the Bourdon tube has been soldered to the spring end-piece. The sleeve is formed in a pipe-shape from a developed material, which is stamped out from a plate made of the electrically conductive metal to have a specific shape.