Adjustable output power supply

An adjustable output power supply (102) with a data communications connector (120, 222) that at least partially complies with physical specifications of a defined data interface standard connector, such as a USB connector. The data communications connector has a number of data contacts (832, 834) and power contacts (830, 832) coupled to and providing output electrical power from a programmable power supply (220). A controller (202) receives an indication of a detection of a feature (302, 516, 616, 802) of a mating connector (122, 514, 614, 804) coupled to the data communications connector, determines (706), based on receiving the detection, at least one resistance value between a data contact and at least one power contact, and adjusts (714) an output voltage of the programmable power supply based on the at least one resistance value.