The standard 30PIN line output port can be directly connected to the Apple dock or Apple audio line input port. No additional line amplification is needed, and the output level can make the sound reach full power output. Through connection and disconnection with various transmission equipment, it realizes cable-free, zero-plugin audio source switching, eliminating the hassle of plugging and unplugging the connection cable to traditional audio equipment to switch the audio source. The user's restraint from the connection cable is lifted, so that the user can enjoy high-fidelity music anywhere in the room without placing the audio source equipment within a meter of the stereo. Technical parameters: Compatible with Bluetooth 2.0 specifications Support A2DP V1.2 The transmission distance is no less than 10 meters.