Abstract: A high-fidelity audio telephone conferencing arrangement which provides talker position information is economically provided between telephone stations over a single standard digital telephone channel. Digitized high-fidelity audio is combined with digitized phase information, derived from talker position detecting circuitry in a local telephone station, and transmitted over the telephone channel to one or more remote telephone stations. A receiver in each remote station decodes the digital information and provides the high-fidelity audio signal to multiple spatially separated acoustic output devices. The digitized pulse information controls "panning" of the audio signal among the acoustic output devices. By varying the level of audio signal flowing to each acoustic device, the position of the talker can be created in a specific position in the remote listener's sound field and the talker's identity thereby more easily determined.

Abstract: A high rate of exchange of information between a control station and each one of multiple associated stations in a key telephone system is economically achieved by using a multipurpose computer in each station to provide the UART function. Serial transmission of asynchronous data is full duplex for the control station and half duplex for ech associated station, with the control station polling a first station and then obtaining that station's response. While the first station is responding, the control station polls a second station and continues in this manner until all the associated stations are polled. The UART function also allows the computer to process other tasks during the same period of time that the serial transmission or reception of data is occurring.

Abstract: A hands-free telephone system is disclosed utilizing an infrared transmitter and receiver to permit wireless speech transmission. The transmitter uses frequency modulation imposed on the infrared signal and includes carrier shift signaling arrangements for indicating a low battery condition and transmitter turn-off. The receiver utilizes a noise detection circuit for permitting remote turn-on, for squelching noise in the voice path, and for feeding an alerting signal to a loudspeaker to indicate that the received signal is excessively noisy. The portable transmitter must then be moved or redirected to provide a better line-of-sight signaling path.