Fully-integrated telephone unit

摘要

A single integrated circuit forms a hands-free telephone unit for use in a digital telephone network and in association with an external keypad, an external microprocessor, an external microphone, and an external speaker. The integrated circuit includes a keypad monitor arranged to provide digital key code signals, an audio processor for supporting hands-free operation, and a digital interface to provide a digital interface between the integrated circuit and the digital network and the external microprocessor.