A medical headlamp assembly, having a headband subassembly, including an electrical network, including a battery and an electrical jack, and a headlamp mount. Also, an electrical headlamp subassembly, has a mounting element matingly and removably engaged to the headlamp mount, and an electrical plug, matingly and removably engaged to the jack and an electrical headlamp, electrically connected to the plug. Further, the headband subassembly produces an electrical input for the headlamp subassembly and the headband subassembly includes a key resistor, the resistance value of which sets a characteristic of the electrical input.