A method for transmitting data signal from a sending-end 100 to a receiving-end 200, comprising the steps of spreading the data signal into a spread spectrum signal, combining the spread signal with an analogue signal into a mixed signal. The mixed signal can be transmitted or broadcasted to the receiving-end 200. The receiving-end is able to play or use the analogue signal without significant noise from the spread spectrum signal. The spread spectrum signal can be retrieved by inverse-spread-processing the spread spectrum signal to retrieve the data signal. The sending-end can be in a headphone 900 and the receiving-end can be in a mobile phone 910, or the sending-end can be a loudspeaker broadcasting the analogue signal to a mobile phone picking up the analogue signal by the microphone in the mobile phone.
