Patent ID: 6058172
Filing Date: 2000-05-02
Classification: H04L,H04M

Abstract:
A telephone circuit comprising:a line interface circuit, coupled to a telephone line, for receiving an FSK signal;a comparator, coupled to the line interface unit, for transforming the FSK signal into a square wave signal with period widths representing a frequency behavior of the FSK signal; anda controller, coupled to the comparator, for measuring the period widths of the square wave signal and for converting the period widths into a data stream corresponding to data encoded in the FSK signal, by determining if the period width has one of a plurality of relationship to one of a plurality of boundary values; anda resynchronization means, coupled to the controller, for causing the controller to resynchronize with the FSK signal to prepare to receive next data encoded in the FSK signal when there is a change in type of digital data obtained from the decoding.