<s>
Doubled	O
signal	O
voltage	O
between	O
the	O
differential	O
pair	O
(	O
compared	O
to	O
a	O
single-ended	O
signal	O
of	O
the	O
same	O
nominal	B-Algorithm
level	I-Algorithm
)	O
,	O
giving	O
6dB	O
extra	O
headroom	O
.	O
</s>
<s>
Differential	O
signalling	O
works	O
for	O
both	O
analog	O
signalling	O
,	O
as	O
in	O
balanced	B-Protocol
audio	I-Protocol
,	O
and	O
in	O
digital	O
signalling	O
,	O
as	O
in	O
RS-422	O
,	O
RS-485	O
,	O
Ethernet	B-Protocol
over	I-Protocol
twisted	I-Protocol
pair	I-Protocol
,	O
PCI	O
Express	O
,	O
DisplayPort	B-Protocol
,	O
HDMI	B-Protocol
and	O
USB	B-Protocol
.	O
</s>
<s>
Differential	O
pairs	O
generally	O
carry	O
differential	O
or	O
semi-differential	O
signals	O
,	O
such	O
as	O
high-speed	O
digital	O
serial	O
interfaces	O
including	O
LVDS	B-Architecture
differential	O
ECL	B-General_Concept
,	O
PECL	B-General_Concept
,	O
LVPECL	B-General_Concept
,	O
Hypertransport	B-Device
,	O
Ethernet	B-Protocol
over	I-Protocol
twisted	I-Protocol
pair	I-Protocol
,	O
Serial	B-Protocol
Digital	I-Protocol
Interface	I-Protocol
,	O
RS-422	O
,	O
RS-485	O
,	O
USB	B-Protocol
,	O
Serial	O
ATA	O
,	O
TMDS	B-Protocol
,	O
FireWire	B-Protocol
,	O
and	O
HDMI	B-Protocol
,	O
etc.	O
,	O
or	O
else	O
high	O
quality	O
and/or	O
high	O
frequency	O
analog	O
signals	O
(	O
e.g.	O
</s>
<s>
video	B-Application
signals	I-Application
,	O
balanced	B-Protocol
audio	I-Protocol
signals	O
,	O
etc	O
.	O
</s>
<s>
SCSI-1	O
variations	O
included	O
a	O
high	O
voltage	O
differential	O
(	O
HVD	O
)	O
implementation	O
whose	O
maximum	O
cable	O
length	O
was	O
many	O
times	O
that	O
of	O
the	O
single-ended	O
version	O
.	O
</s>
<s>
SCSI	B-Architecture
equipment	O
,	O
for	O
example	O
,	O
allows	O
a	O
maximum	O
total	O
cable	O
length	O
of	O
25	O
meters	O
using	O
HVD	O
,	O
while	O
single-ended	O
SCSI	B-Architecture
allows	O
a	O
maximum	O
cable	O
length	O
of	O
1.5	O
to	O
6	O
meters	O
,	O
depending	O
on	O
bus	O
speed	O
.	O
</s>
<s>
LVD	O
versions	O
of	O
SCSI	B-Architecture
allow	O
less	O
than	O
25m	O
cable	O
length	O
not	O
because	O
of	O
the	O
lower	O
voltage	O
,	O
but	O
because	O
these	O
SCSI	B-Architecture
standards	O
allow	O
much	O
higher	O
speeds	O
than	O
the	O
older	O
HVD	O
SCSI	B-Architecture
.	O
</s>
<s>
Low-voltage	B-Architecture
differential	I-Architecture
signalling	I-Architecture
(	O
LVDS	B-Architecture
)	O
,	O
on	O
the	O
other	O
hand	O
,	O
is	O
a	O
specific	O
system	O
defined	O
by	O
a	O
TIA/EIA	O
standard	O
.	O
</s>
<s>
Some	O
integrated	O
circuits	O
dealing	O
with	O
differential	O
signals	O
provide	O
a	O
hardware	O
option	O
(	O
via	O
strapping	B-Device
options	I-Device
,	O
under	O
firmware	O
control	O
,	O
or	O
even	O
automatic	O
)	O
to	O
swap	O
the	O
polarity	O
of	O
the	O
two	O
differential	O
signals	O
,	O
called	O
differential	O
pair	O
swapping	O
,	O
polarity	O
reversion	O
,	O
differential	O
pair	O
inversion	O
,	O
polarity	O
inversion	O
,	O
or	O
lane	O
inversion	O
.	O
</s>
<s>
This	O
can	O
be	O
utilized	O
to	O
simplify	O
or	O
improve	O
the	O
routing	B-Algorithm
of	O
high-speed	O
differential	O
pairs	O
of	O
traces	O
on	O
printed	O
circuit	O
boards	O
in	O
hardware	O
development	O
,	O
to	O
help	O
to	O
cope	O
with	O
common	O
cabling	O
errors	O
through	O
swapped	O
wires	O
,	O
or	O
easily	O
fix	O
common	O
design	O
errors	O
under	O
firmware	O
control	O
.	O
</s>
<s>
PCIe	O
and	O
USB	B-Protocol
SuperSpeed	O
also	O
support	O
lane	O
polarity	O
inversion	O
.	O
</s>
