From: utzoo!decvax!wivax!linus!genrad!mit-eddi!smh
Newsgroups: net.periphs
Title: Re: phase-encoded
Article-I.D.: mit-eddi.130
Posted: Fri Apr 22 10:01:37 1983
Received: Mon Apr 25 06:18:17 1983
References: rayssd.1089

I seem to remember that the I in NRZI stands for Non-Return to Zero Inverted,
or some such thing.  The difference is in whether a zero or one causes a
transition, but I for get which.