A respiratory apparatus includes components to permit different operations of the apparatus with different power supplies. For example, a respiratory therapy apparatus for controlling a respiratory therapy may include a power input circuit to receive a first power or a second power. The first power may be provided by a connectable low-power power supply and the second power by a connectable high-power power supply. A controller of the respiratory apparatus coupled to the power input circuit may be configured to detect one of the power supplies, and based on the detection, selectively activate one of a first mode of operation and a second mode of operation. The first mode of operation may be a non-therapy mode with the first power such as for a data setup or data transfer with the respiratory therapy apparatus and the second mode of operation may be a therapy mode with the second power.
