The Allen-Bradley 1771-P4S REV.B01 USNT is a power supply module engineered for 1771 I/O chassis in PLC-5 control systems. It mounts directly into the rack to deliver regulated power across the backplane to processors and I/O modules. The REV.B01 designation identifies the hardware revision, and the unit is commonly applied in industrial automation panels that rely on legacy 1771 series hardware.
