Phoenix Contact 2966919 A PLC interface is a component that connects a programmable logic controller (PLC) to the rest of the system. It typically consists of a basic terminal block with screw connections and plug-in miniature relays, which are secured to DIN rail type NS 35/7.5 for easy mounting. The interface also features multi-layer gold contacts for secure electrical connections and includes one changeover contact for controlling switching operations. Additionally, it has an input voltage of 12 V DC, making it suitable for various industrial applications.