Coding method for correction and detection of skewed transitions in parallel asynchronous communication systems

A method and apparatus for encoding and decoding a (t1,t2)-skew-tolerant (ST) (t1+s1,t2+s2)-skew-detecting (SD) code, and for correcting and detecting skewed transitions in a parallel asynchronous communication system without acknowledgement, where t1, t2, s1, and s2 are selectable nonnegative integers. Even though transitions sent at the same time in parallel channels may arrive at different times, a limited degree of variation in transmission speeds is permitted between channels. Assume t1 is the maximum correctable number and t1+s1 the maximum detectable number of transitions that can be missing from a first transmitted codeword when the first transition arrives from a second transmitted codeword, and t2 is the maximum correctable number and t2+s2 the maximum detectable number of transitions from the second codeword that can arrive before the last transition of the first codeword arrives. Errors will be corrected and transmissions will be continuous as long as the values of both t1 and t2, as preselected by the user, are not exceeded. If either t1 or t2 is exceeded, a desired control operation will generally be initiated. If the value of either t1 or t2 is exceeded, but the values of both t1+s1 and t2 +s2 are not, then the control operation will always be successful in detecting skew.