<s>
The	O
pulse-code	B-Algorithm
modulation	I-Algorithm
(	O
PCM	B-Algorithm
)	O
technology	O
was	O
patented	O
and	O
developed	O
in	O
France	O
in	O
1938	O
,	O
but	O
could	O
not	O
be	O
used	O
because	O
suitable	O
technology	O
was	O
not	O
available	O
until	O
World	O
War	O
II	O
.	O
</s>
<s>
PCM	B-Algorithm
’s	O
initial	O
goal	O
was	O
that	O
of	O
converting	O
an	O
analog	O
voice	O
telephone	O
channel	O
into	O
a	O
digital	O
one	O
based	O
on	O
the	O
sampling	O
theorem	O
.	O
</s>
<s>
PCM30	B-Protocol
describes	O
an	O
application	O
of	O
pulse-code	B-Algorithm
modulation	I-Algorithm
(	O
PCM	B-Algorithm
)	O
in	O
which	O
30	O
telephony	O
analog	O
signals	O
are	O
binary	O
coded	O
into	O
a	O
digital	O
signal	O
stream	O
.	O
</s>
<s>
This	O
rate	O
is	O
also	O
used	O
in	O
the	O
first	O
stage	O
of	O
European	O
PDH	O
technique	O
,	O
so	O
PCM30	B-Protocol
is	O
also	O
known	O
as	O
E1	O
.	O
</s>
<s>
The	O
PCM30-base	O
system	O
,	O
the	O
analog	O
switching	O
technology	O
in	O
Europe	O
,	O
and	O
served	O
on	O
the	O
digital	O
transmission	O
of	O
telephone	O
traffic	O
.	O
</s>
<s>
The	O
30	O
bytes	O
are	O
,	O
together	O
with	O
a	O
frame	O
ID	O
word	O
,	O
and	O
a	O
channel	O
identifier	O
,	O
bytewise	O
successively	O
sent	O
(	O
see	O
Multiplexer	B-Protocol
)	O
.	O
</s>
<s>
In	O
receiving	O
direction	O
,	O
the	O
30	O
channels	O
are	O
,	O
using	O
a	O
de-multiplexer	O
,	O
converted	O
back	O
to	O
30	O
analogue	O
signals	O
.	O
</s>
<s>
Then	O
,	O
the	O
signals	O
from	O
the	O
multiplexer	B-Protocol
are	O
cyclically	O
sampled	O
at	O
a	O
frequency	O
of	O
8kHz	O
.	O
</s>
<s>
Since	O
2005	O
in	O
Almanya	O
but	O
no	O
PCM30	B-Protocol
lines	O
on	O
HDB3	O
base	O
provided	O
.	O
</s>
