Patent ID: 6163586
Filing Date: 2000-12-19
Classification: H04L

Abstract:
A method for automatic detection of baud rate and character configuration of a received asynchronous serial data stream, by detecting a first predetermined two character sequence from patterns of signal states and their durations,wherein the first predetermined two character sequence comprises either of ""AT"" and ""at"" and the method comprises:a) waiting for a transition from a state corresponding to a stop bit or idle state to a state corresponding to a start bit of a first character;b) measuring the duration of a signal state of the first character begun by said transition;c) determining whether the measured duration falls within any of a set of predetermined bit time ranges, each bit time range corresponding to a different baud rate of a set of predetermined standard baud rates;d) if the measured duration does not fall within any of the predetermined ranges, returning to step a);e) if the measured duration falls within any of the predetermined bit time ranges, determining if the first predetermined two character sequence is received using a standard bit time associated with the bit time range in which the measured duration falls; andf) if it is determined that the first predetermined two character sequence is received using the standard bit time:1. determining the character configuration therefrom; and2. using the standard bit time and determined character configuration for receiving subsequent characters.