<s>
The	O
Digital	O
Signal	O
4/NA	O
(	O
DS4/NA	B-Protocol
)	O
in	O
telecommunications	O
,	O
is	O
a	O
139.264-Mbit/s	O
aggregate-multiplexed	O
signal	O
,	O
equivalent	O
to	O
3	O
Digital	O
Signal	O
3s	O
or	O
2,016	O
Digital	O
Signal	O
0s	O
.	O
</s>
<s>
This	O
link	O
is	O
commonly	O
used	O
for	O
long	O
distance	O
fiber	O
carriage	O
of	O
broadcast	O
radio	O
and	O
television	O
as	O
a	O
platform	O
for	O
the	O
270Mb/sec	O
MPEG-2/ASI	O
Transport	O
Stream	O
.	O
</s>
<s>
Historically	O
,	O
when	O
used	O
with	O
the	O
appropriate	O
gear	O
,	O
the	O
circuit	O
was	O
used	O
to	O
emulate	O
an	O
analog	O
standard	O
definition	O
circuit	O
using	O
a	O
sampling	O
rate	O
of	O
12-15	O
MHz	O
,	O
carrying	O
the	O
samples	O
in	O
PCM	B-Algorithm
format	O
.	O
</s>
