| 摘要 |
An adapter may couple an electronic device to a host such as a computer. When coupled in this way, the host may transfer media files to the device. The host may also supply power to the electronic device using power lines in the adapter. The electronic device may have a status indicator such as a light-emitting diode status indicator. The adapter may also have a status indicator. During operation, the electronic device may transmit coded information on the current state of the status indicator in the electronic device by modulating the status indicator or other load in the device at a selected frequency. Control circuitry in the adapter may detect the transmitted state information by monitoring the power lines. The control circuitry may control the status indicator in the adapter so that the status indicator in the adapter replicates the current state of the status indicator in the electronic device. |
