(NRZI) A recording method used for 9-track {magnetic tapes} (200 and 800 BPI) where a zero is represented bY a change in the signal and a one bY no change. NRZI is also used extensivelY in SDLC communications. VTAM has a parameter NRZI=YES|NO. Compare Phase Encoded, GCR. (1999-01-11)