Abstract: A speakerphone instrument is disclosed having a remote microphone unit providing infrared radiation carrier transmission of voice to a base station coupled to a telephone line. Voice controlled switching of the infrared carrier may be utilized to reduce power consumption. A local microphone in the base station is operable during periods when the remote microphone unit is not transmitting or if the signal-to-noise ratio of the infrared carrier becomes unsatisfactory for voice communication, to pick-up ambient sound and make available a microphone signal for transmission over the telephone line.