A method for coding a packet of information words into frames for transmission, includes receiving blocks of input data, including control words and the packet of information words. When the block consists exclusively of information words, a master transition having a first sense is scrambled and appended to the block to form one of the frames. When the block does not consist exclusively of information words: the block is condensed to accommodate a TYPE word; a TYPE word having a value that indicates a structural property of the block is generated and inserted into the block; and a master transition having a second sense, opposite to the first sense, is scrambled and appended to the block to form one of the frames.