An assembly, method, apparatus, and system for supplying power to security, life safety, information technology, and/or automation system components is disclosed. Some embodiments may include a power supply with a projecting terminal and a cable having a first end with an electrical contact surface for contacting a power transmitting surface of the projecting terminal to establish an electrical connection, so that a first end housing portion surrounds the electrical contact surface and at least partially covers the projecting terminal. The electrical contact surface may be adjustable using a spring, which may also assist in maintaining contact with the power transmitting surface located at the projecting terminal distal end. A cable second end may connect with an electronic device, and may be customizable according to the electronic device. Embodiments may also include keying features for ensuring connection with appropriate power supplies.