<s>
Ethernet	B-Protocol
over	I-Protocol
twisted-pair	I-Protocol
technologies	O
use	O
twisted-pair	O
cables	O
for	O
the	O
physical	B-Application
layer	I-Application
of	O
an	O
Ethernet	O
computer	O
network	O
.	O
</s>
<s>
They	O
are	O
a	O
subset	O
of	O
all	O
Ethernet	B-Protocol
physical	I-Protocol
layers	I-Protocol
.	O
</s>
<s>
Early	O
Ethernet	O
used	O
various	O
grades	O
of	O
coaxial	O
cable	O
,	O
but	O
in	O
1984	O
,	O
StarLAN	B-Protocol
showed	O
the	O
potential	O
of	O
simple	O
unshielded	O
twisted	O
pair	O
.	O
</s>
<s>
This	O
led	O
to	O
the	O
development	O
of	O
10BASE-T	B-Protocol
and	O
its	O
successors	O
100BASE-TX	B-Protocol
,	O
1000BASE-T	O
and	O
10GBASE-T	O
,	O
supporting	O
speeds	O
of	O
10	O
and	O
100megabit	O
per	O
second	O
,	O
then	O
1	O
and	O
10gigabit	O
per	O
second	O
respectively	O
.	O
</s>
<s>
Two	O
new	O
variants	O
of	O
10megabit	O
per	O
second	O
Ethernet	O
over	O
a	O
single	O
twisted	O
pair	O
,	O
known	O
as	O
10BASE-T1S	B-Protocol
and	O
10BASE-T1L	B-Protocol
,	O
were	O
standardized	O
in	O
IEEE	O
Std	O
802.3cg-2019	O
.	O
</s>
<s>
10BASE-T1S	B-Protocol
has	O
its	O
origins	O
in	O
the	O
automotive	O
industry	O
and	O
may	O
be	O
useful	O
in	O
other	O
short-distance	O
applications	O
where	O
substantial	O
electrical	O
noise	O
is	O
present	O
.	O
</s>
<s>
10BASE-T1L	B-Protocol
is	O
a	O
long-distance	O
Ethernet	O
,	O
supporting	O
connections	O
up	O
to	O
1	O
km	O
in	O
length	O
.	O
</s>
<s>
Both	O
of	O
these	O
standards	O
are	O
finding	O
applications	O
implementing	O
the	B-Operating_System
Internet	I-Operating_System
of	I-Operating_System
things	I-Operating_System
.	O
</s>
<s>
The	O
earlier	O
standards	O
use	O
8P8C	O
modular	O
connectors	O
,	O
and	O
supported	O
cable	O
standards	O
range	O
from	O
Category	B-Protocol
3	I-Protocol
to	O
Category	B-Protocol
8	I-Protocol
.	O
</s>
<s>
The	O
first	O
two	O
early	O
designs	O
of	O
twisted-pair	O
networking	O
were	O
StarLAN	B-Protocol
,	O
standardized	O
by	O
the	O
IEEE	O
Standards	O
Association	O
as	O
IEEE	O
802.3e	B-Protocol
in	O
1986	O
,	O
at	O
one	O
megabit	O
per	O
second	O
,	O
and	O
LattisNet	B-Protocol
,	O
developed	O
in	O
January	O
1987	O
,	O
at	O
10	O
megabit	O
per	O
second	O
.	O
</s>
<s>
Both	O
were	O
developed	O
before	O
the	O
10BASE-T	B-Protocol
standard	O
(	O
published	O
in	O
1990	O
as	O
IEEE	O
802.3i	B-Protocol
)	O
and	O
used	O
different	O
signalling	O
,	O
so	O
they	O
were	O
not	O
directly	O
compatible	O
with	O
it	O
.	O
</s>
<s>
The	O
StarLAN10	O
signalling	O
was	O
used	O
as	O
the	O
basis	O
of	O
10BASE-T	B-Protocol
,	O
with	O
the	O
addition	O
of	O
link	O
beat	O
to	O
quickly	O
indicate	O
connection	O
status	O
.	O
</s>
<s>
Using	O
twisted-pair	O
cabling	O
in	O
a	O
star	B-Architecture
topology	I-Architecture
addressed	O
several	O
weaknesses	O
of	O
the	O
previous	O
Ethernet	O
standards	O
:	O
</s>
<s>
Although	O
10BASE-T	B-Protocol
is	O
rarely	O
used	O
as	O
a	O
normal-operation	O
signaling	O
rate	O
today	O
,	O
it	O
is	O
still	O
in	O
wide	O
use	O
with	O
network	B-Protocol
interface	I-Protocol
controllers	I-Protocol
in	O
Wake-on-LAN	B-Protocol
power-down	O
mode	O
and	O
for	O
special	O
,	O
low-power	O
,	O
low-bandwidth	O
applications	O
.	O
</s>
<s>
10BASE-T	B-Protocol
is	O
still	O
supported	O
on	O
most	O
twisted-pair	B-Protocol
Ethernet	I-Protocol
ports	O
with	O
up	O
to	O
Gigabit	O
Ethernet	O
speed	O
.	O
</s>
<s>
The	O
leading	O
number	O
(	O
10	O
in	O
10BASE-T	B-Protocol
)	O
refers	O
to	O
the	O
transmission	O
speed	O
in	O
Mbit/s	O
.	O
</s>
<s>
BASE	O
denotes	O
that	O
baseband	B-Algorithm
transmission	I-Algorithm
is	O
used	O
.	O
</s>
<s>
In	O
some	O
instances	O
the	O
"	O
crossover	B-Protocol
"	O
form	O
(	O
receive	O
to	O
transmit	O
and	O
transmit	O
to	O
receive	O
)	O
may	O
still	O
be	O
required	O
.	O
</s>
<s>
Since	O
these	O
standards	O
differ	O
only	O
in	O
that	O
they	O
swap	O
the	O
positions	O
of	O
the	O
two	O
pairs	O
used	O
for	O
transmitting	O
and	O
receiving	O
,	O
a	O
cable	O
with	O
T568A	O
wiring	O
at	O
one	O
end	O
and	O
T568B	O
wiring	O
at	O
the	O
other	O
results	O
in	O
a	O
crossover	B-Protocol
cable	I-Protocol
.	O
</s>
<s>
A	O
10BASE-T	B-Protocol
or	O
100BASE-TX	B-Protocol
host	O
uses	O
a	O
connector	O
wiring	O
called	O
medium	B-Protocol
dependent	I-Protocol
interfaces	I-Protocol
(	O
MDI	O
)	O
,	O
transmitting	O
on	O
pins	O
1	O
and	O
2	O
and	O
receiving	O
on	O
pins	O
3	O
and	O
6	O
to	O
a	O
network	O
device	O
.	O
</s>
<s>
An	O
infrastructure	O
node	O
(	O
a	O
hub	B-Protocol
or	O
a	O
switch	B-Protocol
)	O
accordingly	O
uses	O
a	O
connector	O
wiring	O
called	O
MDI-X	B-Protocol
,	O
transmitting	O
on	O
pins	O
3	O
and	O
6	O
and	O
receiving	O
on	O
pins	O
1	O
and	O
2	O
.	O
</s>
<s>
Nodes	O
can	O
have	O
two	O
types	O
of	O
ports	O
:	O
MDI	O
(	O
uplink	O
port	O
)	O
or	O
MDI-X	B-Protocol
(	O
regular	O
port	O
,	O
'	O
X	O
 '	O
for	O
internal	O
crossover	B-Protocol
)	O
.	O
</s>
<s>
Hubs	B-Protocol
and	O
switches	O
have	O
regular	O
ports	O
.	O
</s>
<s>
personal	B-Device
computers	I-Device
)	O
have	O
uplink	O
ports	O
.	O
</s>
<s>
When	O
two	O
nodes	O
having	O
the	O
same	O
type	O
of	O
ports	O
need	O
to	O
be	O
connected	O
,	O
a	O
crossover	B-Protocol
cable	I-Protocol
may	O
be	O
required	O
,	O
especially	O
for	O
older	O
equipment	O
.	O
</s>
<s>
Connecting	O
nodes	O
having	O
different	O
types	O
of	O
ports	O
(	O
i.e.	O
,	O
MDI	O
to	O
MDI-X	B-Protocol
and	O
vice	O
versa	O
)	O
requires	O
a	O
straight-through	O
cable	O
.	O
</s>
<s>
Thus	O
connecting	O
an	O
end	O
host	O
to	O
a	O
hub	B-Protocol
or	O
switch	B-Protocol
requires	O
a	O
straight-through	O
cable	O
.	O
</s>
<s>
Some	O
older	O
switches	O
and	O
hubs	B-Protocol
provided	O
a	O
button	O
to	O
allow	O
a	O
port	O
to	O
act	O
as	O
either	O
a	O
normal	O
(	O
regular	O
)	O
or	O
an	O
uplink	O
port	O
,	O
i.e.	O
</s>
<s>
using	O
MDI-X	B-Protocol
or	O
MDI	O
pinout	O
,	O
respectively	O
.	O
</s>
<s>
Many	O
modern	O
Ethernet	O
host	O
adapters	O
can	O
automatically	O
detect	O
another	O
computer	O
connected	O
with	O
a	O
straight-through	O
cable	O
and	O
then	O
automatically	O
introduce	O
the	O
required	O
crossover	B-Protocol
if	O
needed	O
;	O
if	O
neither	O
of	O
the	O
adapters	O
has	O
this	O
capability	O
,	O
then	O
a	O
crossover	B-Protocol
cable	I-Protocol
is	O
required	O
.	O
</s>
<s>
Most	O
newer	O
switches	O
have	O
auto	O
MDI-X	B-Protocol
on	O
all	O
ports	O
allowing	O
all	O
connections	O
to	O
be	O
made	O
with	O
straight-through	O
cables	O
.	O
</s>
<s>
If	O
both	O
devices	O
being	O
connected	O
support	O
1000BASE-T	O
according	O
to	O
the	O
standards	O
,	O
they	O
will	O
connect	O
regardless	O
of	O
whether	O
a	O
straight-through	O
or	O
crossover	B-Protocol
cable	I-Protocol
is	O
used	O
.	O
</s>
<s>
A	O
10BASE-T	B-Protocol
transmitter	O
sends	O
two	O
differential	O
voltages	O
,	O
+	O
2.5V	O
or	O
−	O
2.5V	O
.	O
</s>
<s>
A	O
100BASE-TX	B-Protocol
transmitter	O
sends	O
three	O
differential	O
voltages	O
,	O
+1V	O
,	O
0V	O
,	O
or	O
−1V	O
.	O
</s>
<s>
Unlike	O
earlier	O
Ethernet	O
standards	O
using	O
broadband	B-General_Concept
and	O
coaxial	O
cable	O
,	O
such	O
as	O
10BASE5	O
(	O
thicknet	O
)	O
and	O
10BASE2	O
(	O
thinnet	O
)	O
,	O
10BASE-T	B-Protocol
does	O
not	O
specify	O
the	O
exact	O
type	O
of	O
wiring	O
to	O
be	O
used	O
but	O
instead	O
specifies	O
certain	O
characteristics	O
that	O
a	O
cable	O
must	O
meet	O
.	O
</s>
<s>
This	O
was	O
done	O
in	O
anticipation	O
of	O
using	O
10BASE-T	B-Protocol
in	O
existing	O
twisted-pair	O
wiring	O
systems	O
that	O
did	O
not	O
conform	O
to	O
any	O
specified	O
wiring	O
standard	O
.	O
</s>
<s>
Cable	O
testers	O
are	O
widely	O
available	O
to	O
check	O
these	O
parameters	O
to	O
determine	O
if	O
a	O
cable	O
can	O
be	O
used	O
with	O
10BASE-T	B-Protocol
.	O
</s>
<s>
However	O
,	O
with	O
high-quality	O
cabling	O
,	O
reliable	O
cable	O
runs	O
of	O
150	O
meters	O
or	O
longer	O
are	O
often	O
achievable	O
and	O
are	O
considered	O
viable	O
by	O
technicians	O
familiar	O
with	O
the	O
10BASE-T	B-Protocol
specification	O
.	O
</s>
<s>
100BASE-TX	B-Protocol
follows	O
the	O
same	O
wiring	O
patterns	O
as	O
10BASE-T	B-Protocol
,	O
but	O
is	O
more	O
sensitive	O
to	O
wire	O
quality	O
and	O
length	O
,	O
due	O
to	O
the	O
higher	O
bit	O
rates	O
.	O
</s>
<s>
Data	O
is	O
encoded	O
using	O
4D-PAM5	O
;	O
four	O
dimensions	O
using	O
pulse-amplitude	B-Device
modulation	I-Device
(	O
PAM	O
)	O
with	O
five	O
voltages	O
,	O
−2V	O
,	O
−1V	O
,	O
0V	O
,	O
+1V	O
,	O
and	O
+2V	O
.	O
</s>
<s>
100BASE-TX	B-Protocol
and	O
1000BASE-T	O
were	O
both	O
designed	O
to	O
require	O
a	O
minimum	O
of	O
category	B-Protocol
5	I-Protocol
cable	I-Protocol
and	O
also	O
specify	O
a	O
maximum	O
cable	O
length	O
of	O
.	O
</s>
<s>
Category	B-Protocol
5	I-Protocol
cable	I-Protocol
has	O
since	O
been	O
deprecated	O
and	O
new	O
installations	O
use	O
Category	B-Protocol
5e	I-Protocol
.	O
</s>
<s>
10BASE-T	B-Protocol
and	O
100BASE-TX	B-Protocol
require	O
only	O
two	O
pairs	O
(	O
pins	O
1	O
–	O
2	O
,	O
3	O
–	O
6	O
)	O
to	O
operate	O
.	O
</s>
<s>
Since	O
common	O
Category	B-Protocol
5	I-Protocol
cable	I-Protocol
has	O
four	O
pairs	O
,	O
it	O
is	O
possible	O
to	O
use	O
the	O
spare	O
pairs	O
(	O
pins	O
4	O
–	O
5	O
,	O
7	O
–	O
8	O
)	O
in	O
10	O
-	O
and	O
100-Mbit/s	O
configurations	O
for	O
other	O
purposes	O
.	O
</s>
<s>
The	O
spare	O
pairs	O
may	O
be	O
used	O
for	O
power	B-Device
over	I-Device
Ethernet	I-Device
(	O
PoE	B-Device
)	O
,	O
for	O
two	O
plain	O
old	O
telephone	O
service	O
(	O
POTS	O
)	O
lines	O
,	O
or	O
for	O
a	O
second	O
10BASE-T	B-Protocol
or	O
100BASE-TX	B-Protocol
connection	O
.	O
</s>
<s>
In	O
practice	O
,	O
great	O
care	O
must	O
be	O
taken	O
to	O
separate	O
these	O
pairs	O
as	O
10/100-Mbit/s	O
Ethernet	O
equipment	O
electrically	O
terminates	O
the	O
unused	O
pins	O
(	O
"	O
Bob	O
Smith	O
Termination	O
"	O
)	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
more	O
computer-oriented	O
two	O
and	O
four-pair	O
variants	O
,	O
the	O
10BASE-T1	O
,	O
100BASE-T1	O
and	O
1000BASE-T1	O
single-pair	O
Ethernet	B-Protocol
physical	I-Protocol
layers	I-Protocol
are	O
intended	O
for	O
industrial	O
and	O
automotive	O
applications	O
or	O
as	O
optional	O
data	O
channels	O
in	O
other	O
interconnect	O
applications	O
.	O
</s>
<s>
Both	O
physical	B-Application
layers	I-Application
require	O
a	O
balanced	O
twisted	O
pair	O
with	O
an	O
impedance	O
of	O
100Ω	O
.	O
</s>
<s>
Similar	O
to	O
PoE	B-Device
,	O
Power	O
over	O
Data	O
Lines	O
(	O
PoDL	O
)	O
can	O
provide	O
up	O
to	O
50W	O
to	O
a	O
device	O
.	O
</s>
<s>
8P8C	O
modular	O
connector	O
:	O
For	O
stationary	O
uses	O
in	O
controlled	O
environments	O
,	O
from	O
homes	O
to	O
datacenters	B-Operating_System
,	O
this	O
is	O
the	O
dominant	O
connector	O
.	O
</s>
<s>
Bandwidths	B-Algorithm
supporting	O
up	O
to	O
Cat	O
8	O
cabling	O
are	O
defined	O
for	O
this	O
connector	O
format	O
.	O
</s>
<s>
Nominal	O
bandwidth	B-Algorithm
is	O
500MHz	O
(	O
Cat	B-Protocol
6A	I-Protocol
)	O
.	O
</s>
<s>
Standardized	O
as	O
IEC	O
61076-3-124	O
,	O
its	O
nominal	O
bandwidth	B-Algorithm
is	O
500MHz	O
(	O
Cat	B-Protocol
6A	I-Protocol
)	O
.	O
</s>
<s>
Ethernet	B-Protocol
over	I-Protocol
twisted-pair	I-Protocol
standards	O
up	O
through	O
Gigabit	O
Ethernet	O
define	O
both	O
full-duplex	O
and	O
half-duplex	O
communication	O
.	O
</s>
<s>
Higher	O
speed	O
standards	O
,	O
2.5GBASE-T	O
up	O
to	O
40GBASE-T	O
running	O
at	O
2.5	O
to	O
40Gbit/s	O
,	O
consequently	O
define	O
only	O
full-duplex	O
point-to-point	O
links	O
which	O
are	O
generally	O
connected	O
by	O
network	B-Protocol
switches	I-Protocol
,	O
and	O
do	O
not	O
support	O
the	O
traditional	O
shared-medium	O
CSMA/CD	O
operation	O
.	O
</s>
<s>
Many	O
different	O
modes	O
of	O
operations	O
(	O
10BASE-T	B-Protocol
half-duplex	O
,	O
10BASE-T	B-Protocol
full-duplex	O
,	O
100BASE-TX	B-Protocol
half-duplex	O
,	O
etc	O
.	O
)	O
</s>
<s>
exist	O
for	O
Ethernet	B-Protocol
over	I-Protocol
twisted	I-Protocol
pair	I-Protocol
,	O
and	O
most	O
network	B-Protocol
adapters	I-Protocol
are	O
capable	O
of	O
different	O
modes	O
of	O
operation	O
.	O
</s>
<s>
Autonegotiation	B-Protocol
is	O
required	O
in	O
order	O
to	O
make	O
a	O
working	O
1000BASE-T	O
connection	O
.	O
</s>
<s>
When	O
two	O
linked	O
interfaces	O
are	O
set	O
to	O
different	O
duplex	O
modes	O
,	O
the	O
effect	O
of	O
this	O
duplex	B-Protocol
mismatch	I-Protocol
is	O
a	O
network	O
that	O
functions	O
much	O
more	O
slowly	O
than	O
its	O
nominal	O
speed	O
.	O
</s>
<s>
Duplex	B-Protocol
mismatch	I-Protocol
may	O
be	O
inadvertently	O
caused	O
when	O
an	O
administrator	O
configures	O
an	O
interface	O
to	O
a	O
fixed	O
mode	O
(	O
e.g.	O
</s>
<s>
100Mbit/s	O
full-duplex	O
)	O
and	O
fails	O
to	O
configure	O
the	O
remote	O
interface	O
,	O
leaving	O
it	O
set	O
to	O
autonegotiate	B-Protocol
.	O
</s>
