in terms of payload per unit bandwidth,
UUCP moving email or netnews batches is
still one of the most efficient encodings
available. with "G-protocol spoofing"
enabled on a Telebit Trailblazer, you can
get more useful payloads bits/second over
the most eggregious circuits than any other
scheme I know about. hmm - it's interesting
to contemplate a Trailblazer running over an HF
connection. I suspect it doesn't retrain often
enough, but it is the first widely-deployed
implementation of OFDM (orthogonal Frequency
Divison Multiplexing) and for it's day, it
was a stunning achievement. In fact, it took
a long time for "ITU Standard" dialup modems
to come within lightyears of the TB's performance.

-mo