Method and apparatus for caller-controlled receipt and delivery of voice

Abstract

A line interface unit for caller-controlled receipt and delivery of voice and/or data meassages over a telephone system having a voice/data message facility, the message facility connectible to at least one calling station and a called station and normally having access prevention circuitry for preventing storage and forwarding of voice/data messages unless predetermined access codes are received and verified by the circuitry. In the preferred embodiment, the unit comprises a switch connected to a central office and having first and second positions and wherein signals are connected directly between the calling station and the central office when the switch is in the first position. The interface unit also includes circuitry for signaling the message facility and circuitry for monitoring call progress upon call initiation to the called station. Microprocessor-based control circuitry responds to detection of a predetermined condition at the called station upon call initiation, to detection of a first predetermined code from the calling station indicating that the caller desires to leave a voice/data message for the called station, and to detection of a second predetermined code from the voice message facility, to establish a connection between the calling station and the message facility. Thereafter, a special data string is transmitted to the message facility which, upon receipt thereby, facilitates barrierless entry in and out of the message facility without the predetermined access codes.