<s>
MLT-3	B-Protocol
encoding	I-Protocol
(	O
Multi-Level	O
Transmit	O
)	O
is	O
a	O
line	B-Protocol
code	I-Protocol
(	O
a	O
signaling	O
method	O
used	O
in	O
a	O
telecommunication	O
system	O
for	O
transmission	O
purposes	O
)	O
that	O
uses	O
three	O
voltage	O
levels	O
.	O
</s>
<s>
An	O
MLT-3	B-Protocol
interface	O
emits	O
less	O
electromagnetic	O
interference	O
and	O
requires	O
less	O
bandwidth	B-Algorithm
than	O
most	O
other	O
binary	O
or	O
ternary	B-Language
interfaces	O
that	O
operate	O
at	O
the	O
same	O
bit	O
rate	O
(	O
see	O
PCM	B-Algorithm
for	O
discussion	O
on	O
bandwidth	B-Algorithm
/	O
quantization	B-Algorithm
tradeoffs	O
)	O
,	O
such	O
as	O
Manchester	B-Protocol
code	I-Protocol
or	O
Alternate	B-Protocol
Mark	I-Protocol
Inversion	I-Protocol
.	O
</s>
<s>
MLT-3	B-Protocol
cycles	O
sequentially	O
through	O
the	O
voltage	O
levels	O
−1	O
,	O
0	O
,	O
+1	O
,	O
0	O
.	O
</s>
<s>
Similar	O
to	O
simple	O
NRZ	B-Protocol
encoding	I-Protocol
,	O
MLT-3	B-Protocol
has	O
a	O
coding	O
efficiency	O
of	O
1	O
bit/baud	O
,	O
however	O
it	O
requires	O
four	O
transitions	O
(	O
baud	O
)	O
to	O
complete	O
a	O
full	O
cycle	O
(	O
from	O
low-to-middle	O
,	O
middle-to-high	O
,	O
high-to-middle	O
,	O
middle-to-low	O
)	O
.	O
</s>
<s>
it	O
must	O
be	O
pre-coded	O
using	O
a	O
run-length	B-Protocol
limited	I-Protocol
code	I-Protocol
.	O
</s>
<s>
MLT-3	B-Protocol
was	O
first	O
introduced	O
by	O
Crescendo	O
Communications	O
as	O
a	O
coding	O
scheme	O
for	O
FDDI	B-Protocol
copper	O
interconnect	O
(	O
TP-PMD	O
,	O
aka	O
CDDI	B-Protocol
)	O
.	O
</s>
<s>
Later	O
,	O
the	O
same	O
technology	O
was	O
used	O
in	O
the	O
100BASE-TX	B-Protocol
physical	O
medium	O
dependent	O
sublayer	O
,	O
given	O
the	O
considerable	O
similarities	O
between	O
FDDI	B-Protocol
and	O
100BASE-[TF]X	B-Protocol
physical	O
media	O
attachment	O
layer	O
(	O
section	O
25.3	O
of	O
IEEE802.3-2002	O
specifies	O
that	O
ANSI	O
X3.263:1995	O
TP-PMD	O
should	O
be	O
consulted	O
,	O
with	O
minor	O
exceptions	O
)	O
.	O
</s>
<s>
Signaling	O
specified	O
by	O
100BASE-T4	O
Ethernet	O
,	O
while	O
it	O
has	O
three	O
levels	O
,	O
is	O
not	O
compatible	O
with	O
MLT-3	B-Protocol
.	O
</s>
<s>
It	O
uses	O
selective	O
base-2	O
to	O
base-3	B-Algorithm
conversion	O
with	O
direct	O
mapping	O
of	O
base-3	B-Algorithm
digits	O
to	O
line	O
levels	O
(	O
8B6T	O
code	O
)	O
.	O
</s>
