Electronic device, accessory, and method for detecting an accessory

An accessory for an electronic device, comprising:

• a connector for connecting to the electronic device;
• a microphone;
• a microphone line configured to connect the microphone to the connector;
• a control interface unit;
• a controller, having a plurality of terminals including a power terminal, a data terminal, and a plurality of control terminals, wherein the power terminal is coupled to the microphone line, the data terminal is coupled to the microphone line, and the control terminals are coupled to the control interface unit;
• wherein when the connector is connected to the electronic device, the power terminal receives a power signal for powering the controller, and in response to a command, which is represented by a first serial digital signal and received through the microphone line and the data terminal from the electronic device, the controller sends an identification of the accessory, which is represented by a second serial digital signal, through the data terminal and the microphone line to the electronic device,
• wherein when the identification of the accessory is received by the electronic device, the electronic device enters a first operation mode and operates in response to a control signal;
• or if the identification of the accessory is not received by the electronic device, the electronic device enters a second operation mode and operates in response to a voltage level at an audio contact of the electronic device when the accessory is electrically connected to the electronic device.

A method, implemented in an electronic device having a connector, for detecting an accessory, comprising:

• when the accessory is electrically connected to the electronic device, providing the power signal at an audio contact of the connector;
• sending a command, which is represented by a first serial digital signal, to the accessory through the audio contact;
• determining whether an identification of the accessory, which is represented by a second digital signal, is received at the audio contact;
• when the identification of the accessory is received, determining the accessory is of a first type, and the electronic device enters a first operation mode and operates in response to a control signal;
• otherwise, determining the accessory is of a second type, and the electronic device enters a second operation mode and operates in response to a voltage level at an audio contact of the electronic device when the accessory is electrically connected to the electronic device.