<s>
An	O
Ethernet	B-Protocol
crossover	I-Protocol
cable	I-Protocol
is	O
a	O
crossover	B-Protocol
cable	I-Protocol
for	O
Ethernet	O
used	O
to	O
connect	O
computing	O
devices	O
together	O
directly	O
.	O
</s>
<s>
two	O
computers	O
(	O
via	O
their	O
network	B-Protocol
interface	I-Protocol
controllers	I-Protocol
)	O
or	O
two	O
switches	O
to	O
each	O
other	O
.	O
</s>
<s>
By	O
contrast	O
,	O
straight	O
through	O
patch	B-Device
cables	I-Device
are	O
used	O
to	O
connect	O
devices	O
of	O
different	O
types	O
,	O
such	O
as	O
a	O
computer	O
to	O
a	O
network	B-Protocol
switch	I-Protocol
.	O
</s>
<s>
Intentionally	O
crossed	O
wiring	O
in	O
the	O
crossover	B-Protocol
cable	I-Protocol
connects	O
the	O
transmit	O
signals	O
at	O
one	O
end	O
to	O
the	O
receive	O
signals	O
at	O
the	O
other	O
end	O
.	O
</s>
<s>
Many	O
network	B-Device
devices	I-Device
today	O
support	O
auto	O
MDI-X	O
(	O
aka	O
"	O
auto	O
crossover	O
"	O
)	O
capability	O
,	O
wherein	O
a	O
patch	B-Device
cable	I-Device
can	O
be	O
used	O
in	O
place	O
of	O
a	O
crossover	B-Protocol
cable	I-Protocol
,	O
or	O
vice	O
versa	O
,	O
and	O
the	O
receive	O
and	O
transmit	O
signals	O
are	O
reconfigured	O
automatically	O
within	O
the	O
device	O
to	O
yield	O
a	O
working	O
connection	O
.	O
</s>
<s>
The	O
10BASE-T	B-Protocol
and	O
100BASE-TX	B-Protocol
Ethernet	O
standards	O
use	O
one	O
wire	O
pair	O
for	O
transmission	O
in	O
each	O
direction	O
.	O
</s>
<s>
The	O
10BASE-T	B-Protocol
standard	O
was	O
devised	O
to	O
be	O
used	O
with	O
existing	O
twisted	O
pair	O
cable	O
installations	O
with	O
straight-through	O
connections	O
.	O
</s>
<s>
Since	O
10BASE-T	B-Protocol
and	O
100BASE-TX	B-Protocol
use	O
pairs	O
2	O
and	O
3	O
,	O
these	O
two	O
pairs	O
must	O
be	O
swapped	O
in	O
the	O
cable	O
.	O
</s>
<s>
This	O
wiring	O
scheme	O
constitutes	O
a	O
crossover	B-Protocol
cable	I-Protocol
.	O
</s>
<s>
A	O
crossover	B-Protocol
cable	I-Protocol
may	O
also	O
be	O
used	O
to	O
connect	O
two	O
hubs	O
or	O
two	O
switches	O
on	O
their	O
upstream	O
ports	O
.	O
</s>
<s>
Because	O
the	O
only	O
difference	O
between	O
the	O
T568A	O
and	O
T568B	O
pin	O
and	O
pair	O
assignments	O
are	O
that	O
pairs	O
2	O
and	O
3	O
are	O
swapped	O
,	O
a	O
crossover	B-Protocol
cable	I-Protocol
may	O
be	O
envisioned	O
as	O
a	O
cable	O
with	O
one	O
modular	B-Architecture
connector	I-Architecture
following	O
T568A	O
and	O
the	O
other	O
T568B	O
(	O
see	O
TIA/EIA	O
-568	O
wiring	O
)	O
.	O
</s>
<s>
Such	O
a	O
cable	O
will	O
work	O
for	O
10BASE-T	B-Protocol
or	O
100BASE-TX	B-Protocol
.	O
</s>
<s>
If	O
one	O
or	O
both	O
of	O
two	O
connected	O
devices	O
has	O
the	O
automatic	O
MDI/MDI	O
-X	O
configuration	O
feature	O
,	O
there	O
is	O
no	O
need	O
for	O
crossover	B-Protocol
cables	I-Protocol
.	O
</s>
<s>
In	O
a	O
departure	O
from	O
both	O
10BASE-T	B-Protocol
and	O
100BASE-TX	B-Protocol
,	O
1000BASE-T	O
and	O
faster	O
use	O
all	O
four	O
cable	O
pairs	O
for	O
simultaneous	O
transmission	O
in	O
both	O
directions	O
through	O
the	O
use	O
of	O
telephone	O
hybrid-like	O
signal	O
handling	O
.	O
</s>
<s>
For	O
this	O
,	O
fiber	O
patch	B-Device
cables	I-Device
with	O
duplex	O
connectors	B-Device
are	O
normally	O
configured	O
as	O
crossover	O
as	O
is	O
the	O
on-premises	B-Protocol
wiring	I-Protocol
.	O
</s>
<s>
Thus	O
,	O
a	O
simple	O
connection	O
with	O
two	O
patch	B-Device
cables	I-Device
at	O
each	O
end	O
and	O
a	O
section	O
of	O
fixed	O
cable	O
in	O
the	O
middle	O
has	O
three	O
crossovers	O
in	O
total	O
,	O
resulting	O
in	O
a	O
working	O
connection	O
.	O
</s>
<s>
Patch	B-Device
cable	I-Device
crossovers	O
can	O
usually	O
be	O
reconfigured	O
very	O
easily	O
by	O
swapping	O
the	O
connectors	B-Device
within	O
a	O
duplex	O
bracket	O
if	O
required	O
.	O
</s>
<s>
In	O
practice	O
,	O
it	O
does	O
not	O
matter	O
if	O
non-crossover	O
Ethernet	B-Protocol
cables	I-Protocol
are	O
wired	O
as	O
T568A	O
or	O
T568B	O
,	O
just	O
so	O
long	O
as	O
both	O
ends	O
follow	O
the	O
same	O
wiring	O
format	O
.	O
</s>
<s>
This	O
is	O
the	O
most	O
common	O
kind	O
of	O
crossover	B-Protocol
cable	I-Protocol
.	O
</s>
