- Analog Station Set and Central Office Line Protector- Protects up to 4-wires (2-pairs) per jack. Using RJ11/45 connectors (2in/2out pins 3 6 4 5 protected) - Auto-Resetting Technology: PTC resistors open when a surge occurs protecting your equipment but unlike other fuses the PTCs close again once the surge passes. - Expandable modular system - Applications: Analog and Central Office lines for PBX or KSU Agency Approval: UL 497A (Secondary) - Grounding Requirements: Uses Electrical AC Ground - Recommended Grounding Impedance: