Patent ID: 6381309
Filing Date: 2002-04-30
Classification: H04M

Abstract:
A Telephone Device for the Deaf (TDD) transitive adapted for TDD signaling and associated with a computer, the TDD transitive comprising:a) a sound processor adapted to receive a digital audio signal and generate a transmit audio signal, wherein said sound processor is a sound card adapted to sample an analog signal to generate said digital audio signal and interface with a computing system, said sound card having a first audio input and a first audio output; b) a correlator provided in the computer and adapted to discriminate between at least two audio tone states found in said digital audio signal and to output a received data stream signal, wherein said correlator discriminates between said at least two audio tone states a number of times per bit time slot, said correlator determining bit values based on a count of said audio tone states discriminated; and c) a Plain Old Telephone Service (POTS) connector adapted to connect said first audio input and said first audio output to a local loop and to match an impedance of a local loop to an impedance of said first audio input and to an impedance of said first audio output.