<s>
A	O
bipolar	B-Protocol
violation	I-Protocol
,	O
bipolarity	O
violation	O
,	O
or	O
BPV	O
,	O
is	O
a	O
violation	O
of	O
the	O
bipolar	B-Protocol
encoding	I-Protocol
rules	O
where	O
two	O
pulses	O
of	O
the	O
same	O
polarity	O
occur	O
without	O
an	O
intervening	O
pulse	B-Algorithm
of	O
the	O
opposite	O
polarity	O
.	O
</s>
<s>
T-carrier	O
and	O
E-carrier	O
signals	O
are	O
transmitted	O
using	O
a	O
scheme	O
called	O
bipolar	B-Protocol
encoding	I-Protocol
,	O
a.k.a.	O
</s>
<s>
Alternate	O
Mark	O
Inversion	O
(	O
AMI	O
)	O
,	O
where	O
ONE	O
is	O
represented	O
by	O
a	O
pulse	B-Algorithm
,	O
and	O
a	O
ZERO	O
is	O
represented	O
by	O
no	O
pulse	B-Algorithm
.	O
</s>
<s>
To	O
ensure	O
that	O
this	O
is	O
always	O
present	O
,	O
there	O
exist	O
a	O
number	O
of	O
modified	B-Protocol
AMI	I-Protocol
codes	I-Protocol
which	O
use	O
judiciously	O
placed	O
bipolar	B-Protocol
violations	I-Protocol
to	O
encode	O
long	O
strings	O
of	O
consecutive	O
zeroes	O
.	O
</s>
