Abstract: A programmable customized universal digital listening system is provided with one or more digital signal processor chips which are implemented as one or more digital filters whose parameters are established by one or more erasable programmable read-only memories (EPROMs). The information included in the EPROMs directed to the parameters of the digital filters are determined based upon the user's response to various audio signals provided from an audiologist. Based upon these responses, the EPROMs are programmed. Additionally, this listening system is provided with an additional digital filter which changes its responses based upon the frequency of any background noise.

Abstract: A Digital Service (DS) interface interfaces a Personal Computer (PC) to the DS directly at the PC's data bus. The DS interface has independent transmit and receive memories for transmitting and receiving the digital data at high speeds. FIFO memories buffer data between the PC's data bus and the DS interface prior to being converted to bipolar digital signals before transmission and after being received and converted to amplitude discrete digital signals from bipolar digital signals.

Abstract: A conferencing bridge provides conferencing capabilities for a plurality of input lines and for a plurality of output lines. The conferencing bridge has a signal processor which processes the audio information transferred between the input lines and the output lines. A plurality of codecs analog to digital conversion and digital to analog conversion for interfacing the signal processor to the plurality of input lines and output lines. A control processor is operatively connected to the signal processor and controls and operation of the signal processor as well as the conferencing bridge through number codes that are inputted to the conference bridge via the telephone key pad. A tone converter converts the inputted tones to digital information to which the control processor will respond. The signal processor provides not only identification of the telephone line on which a speaker is talking but also performs an amplitude adjustment so that there is a minimum loss involved for the conferencing network.