An adjustable output power supply with a data communications connector 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 and power contacts coupled to and providing output electrical power from a programmable power supply. A controller receives an indication of a detection of a feature of a mating connector coupled to the data communications connector, determines, based on receiving the detection, at least one resistance value between a data contact and at least one power contact, and adjusts an output voltage of the programmable power supply based on the at least one resistance value.