An interface between a programming system and a set of headphones allows the transmission of both audio and digital data over analog audio signal lines of the headphones. Circuitry on the programming system is configured to transmit digital data over the analog audio signal lines by either modulating a carrier frequency with the digital data such that the digital data is transmitted over non-audible frequencies or by time-multiplexing the transmission of digital data and analog audio data. Circuitry on the headphones is configured to receive digital data by demodulating the modulated digital data or by de-multiplexing the time-multiplexed digital and analog audio data. In other embodiments of acoustic headphones which include microphones, a Talk-Through functionality may be implemented.