Patent ID: 8213625

Claim:
A method of detecting coupling of a headset to an intercom system, wherein the headset comprises: an acoustic driver to acoustically output audio to an ear of a user; a communications microphone to detect speech sounds of the user; a wireless transceiver to wirelessly couple the headset to a wireless device; a cable assembly to couple the headset to an intercom system, the cable assembly comprising: an audio conductor used to convey a signal representing audio to the acoustic driver; a ground conductor associated with the audio conductor; and a pair of microphone conductors used to convey signals representing audio detected by the communications microphone; an excitation current injector to inject a current into the audio conductor; a voltage sensor to monitor a voltage of the of the audio conductor relative to the ground conductor; and a controller coupled to the excitation current injector and the voltage sensor; the method comprising: the excitation current injector injecting a current into the audio conductor; the voltage sensor monitoring the voltage of the audio conductor relative to the ground conductor; the controller determining that the audio conductor is coupled to the intercom system in response to the monitored voltage being within a first range of voltages; and determining that the audio conductor is not coupled to the intercom system in response to the monitored voltage being within a second range of voltages, wherein the second range of voltages is higher than the first range of voltages.