Mariusz SP3FXC wrote:

Moebius Velcro wrote:

Mariusz SP3FXC wrote:
I'm looking for some info on NRZI coding. google gives me useless
links... nothing special. I am about to write someting that uses NRZI but
i can not find any specification.

If you look at this with a monospaced font (Courier for example) it
should make sense:

__ ________ _____ __
__| |__| |__| |________|
0 0 0 1 1 0 0 1 0 1 1 0

Non-Return Zero Inverting means (1) the signal does not return
to a resting state after a bit, and (2) a zero is indicated by
a change of state, and a one by no change. Clock is extracted
from the data, which means there must be a limit to the number
of consecutive 1's, and the "zero stuffing" technique leads to
a bigger discussion.

HTH

Very good One more question. Is it "level-sensitive" coding? I mean if we
change the phase (by 180deg.) of NRZI coded signal would it be still
readable when it hits decoder? I need to verify this because it is
essential for my project.

No.

__ ________ _____ __
__| |__| |__| |________|

means the same as
__ __ __ ________
|__| |________| |_____| |__

in that a zero is represented by a change, in either direction,
and a one is no change.

;B