1. A transmitter apparatus comprising: a power transmitter for wirelessly coupling with a power receiver of a mobile device, the power transmitter comprising a planar winding configured to exchange a power signal with the power receiver wirelessly by magnetic induction; and a non-transitory computer readable storage medium comprising computer program instructions that when executed by a processor of the transmitter apparatus cause the power transmitter to modulate the power signal sent to the power receiver according to one of a plurality of modulations, each modulation associated with one of a plurality of operational modes for the mobile device, wherein responsive to receiving the modulated power signal, the mobile device initiates a function associated with one of the plurality of operational modes corresponding to the one of the plurality of modulations, and wherein (i) the one of the plurality of modulations used by the power transmitter, (ii) the one of the plurality of operational modes and the corresponding function initiated on the mobile device in response to the one of the plurality of modulations are: (a) selected based on a physical location of the power transmitter, or (b) pre-selected for the power transmitter.