IBM XT 5160 Technical Reference page 395

non-return-to-zero change-on-ones recording (NRZI). A
transmission encoding method in which the data terminal
equipment changes the signal to the opposite state to send a
binary 1 and leaves it in the same state to send a binary
o.
non-return-to-zero (inverted) recording (NRZI). Deprecated term
for non-return-to-zero change-on-ones recording.
NOR. A logic operator having the property that if P is a
statement,
Q
is a statement, R is a statement,... , then the NOR of
P,
Q,
R, ... is true if all statements are false, false if at least one
statement is true.
NOR gate. A gate in which the output is 0 only if at least one
input is 1.
NOT. A logical operator having the property that if P is a
statement, then the NOT of P is true if P is false, false if P is true.
NRZI. Non-return-to-zero change-on-ones recording.
ns. Nanosecond; 0.000,000,001 second.
NUL. The null character.
null character (NUL). A control character that is used to
accomplish media-fill or time-fill, and that may be inserted into or
removed from, a sequence of characters without affecting the
meaning of the sequence; however, the control of the equipment
or the format may be affected by this character.
odd-even check. Synonym for parity check.
offline. Pertaining to the operation of a functional unit without
the continual control of a computer.
one-shot. A circuit that delivers one output pulse of desired
duration for each input (trigger) pulse.
open circuit. ( 1) A discontinuous circuit; that is, one that is
broken at one or more points and, consequently, cannot conduct
current. Contrast with closed circuit. (2) Pertaining to a no-load
condition; for example, the open-circuit voltage of a power
supply.
Glossary-24