a data transmission method and apparatus provides for transmitting lower data rate information in a higher data transmission rate environment . information entities to be transmitted are broken into smaller entitles called nyblets . higher data transmission rates are accomodated by accelerating a clock and clocking nyblets from memory at rate that allows the nyblets to be serially assembled into expected bit length words . lower data rate information , which in conventional systems was transmitted redundantly to achieve compatibility with higher data rate systems , is now transmitted without duplication as a plurality of nyblets in series until the expected bit length is achieved . the result is that more information can be transmitted over a communication medium , since duplicate or redundant transmission of lower data rate information is avoided .