A new delay-insensitive data encoding scheme for global communication,
level-encoded transition signaling (LETS), is introduced.
LETS is a generalization of level-encoded dual rail (LEDR),
an earlier non-return-to-zero encoding scheme where one of two wires changes
value per data bit per transaction.
In LETS, only one of $N=2^n$ (1-of-$N$) wire changes value per n data bits per
transaction. Compared to most common return-to-zero encoding schemes,
LETS has potential
power and throughput advantages, since fewer rails switch and no
return-to-zero phase is required.
Compared to existing non-return-to-zero schemes (i.e., LEDR),
higher-dimension LETS codes have a potential power advantage,
with significantly reduced switching activity per data bit.
Two alternative 1-of-4 LETS codes are proposed,
and efficient hardware for completion detection
and conversion to return-to-zero protocols is introduced.
Finally, a general theoretical framework is presented which
characterizes the properties of arbitrary 1-of-$N$ LETS codes,
as well as a simple procedure to generate such codes.