  It is well known that orthogonal coding can be used to approach the Shannon
capacity of the power-constrained AWGN channel without a bandwidth constraint.
This correspondence describes a semi-orthogonal variation of pulse position
modulation that is sequential in nature -- bits can be ``streamed across''
without having to buffer up blocks of bits at the transmitter. ML decoding
results in an exponentially small probability of error as a function of
tolerated receiver delay and thus eventually a zero probability of error on
every transmitted bit. In the high-rate regime, a matching upper bound is given
on the delay error exponent. We close with some comments on the case with
feedback and the connections to the capacity per unit cost problem.
