In one embodiment, a circuit includes an audio jack that receives a connector of an external transducer. The circuit also includes an amplifier coupled to the audio jack and configured to amplify a signal associated with the external transducer. The circuit further includes a plurality of connection lines coupled to the amplifier and configured to relay the signal between the amplifier and a plurality of audio jacks of independent computing devices. The circuit additionally includes one or more resistors that provide resistance to each of the connection lines. A resistance of a particular one of the connection lines is sufficient to cause the computing device coupled to the particular connection line to recognize the particular connection line as an external transducer.