<s>
G.726	B-Algorithm
is	O
an	O
ITU-T	O
ADPCM	B-Algorithm
speech	B-Application
codec	I-Application
standard	O
covering	O
the	O
transmission	O
of	O
voice	O
at	O
rates	O
of	O
16	O
,	O
24	O
,	O
32	O
,	O
and	O
40kbit/s	O
.	O
</s>
<s>
It	O
was	O
introduced	O
to	O
supersede	O
both	O
G.721	B-Algorithm
,	O
which	O
covered	O
ADPCM	B-Algorithm
at	O
32kbit/s	O
,	O
and	O
G.723	B-Algorithm
,	O
which	O
described	O
ADPCM	B-Algorithm
for	O
24	O
and	O
40kbit/s	O
.	O
</s>
<s>
G.726	B-Algorithm
also	O
introduced	O
a	O
new	O
16kbit/s	O
rate	O
.	O
</s>
<s>
The	O
four	O
bit	O
rates	O
associated	O
with	O
G.726	B-Algorithm
are	O
often	O
referred	O
to	O
by	O
the	O
bit	O
size	O
of	O
a	O
sample	B-Algorithm
,	O
which	O
are	O
2	O
,	O
3	O
,	O
4	O
,	O
and	O
5-bits	O
respectively	O
.	O
</s>
<s>
The	O
corresponding	O
wide-band	O
codec	O
based	O
on	O
the	O
same	O
technology	O
is	O
G.722	B-Algorithm
.	O
</s>
<s>
The	O
most	O
commonly	O
used	O
mode	O
is	O
32kbit/s	O
,	O
which	O
doubles	O
the	O
usable	O
network	O
capacity	O
by	O
using	O
half	O
the	O
rate	O
of	O
G.711	B-Algorithm
.	O
</s>
<s>
It	O
is	O
primarily	O
used	O
on	O
international	O
trunks	O
in	O
the	O
phone	O
network	O
and	O
is	O
the	O
standard	O
codec	O
used	O
in	O
DECT	B-Protocol
wireless	O
phone	O
systems	O
.	O
</s>
<s>
The	O
principal	O
application	O
of	O
24	O
and	O
16	O
kbit/s	O
channels	O
is	O
for	O
overload	O
channels	O
carrying	O
voice	O
in	O
digital	B-Protocol
circuit	I-Protocol
multiplication	I-Protocol
equipment	I-Protocol
(	O
DCME	B-Protocol
)	O
.	O
</s>
<s>
The	O
principal	O
application	O
of	O
40	O
kbit/s	O
channels	O
is	O
to	O
carry	O
data	O
modem	B-Application
signals	O
in	O
DCME	B-Protocol
,	O
especially	O
for	O
modems	B-Application
operating	O
at	O
greater	O
than	O
4800	O
bit/s	O
.	O
</s>
<s>
G.721	B-Algorithm
was	O
introduced	O
in	O
1984	O
,	O
while	O
G.723	B-Algorithm
was	O
introduced	O
in	O
1988	O
.	O
</s>
<s>
They	O
were	O
folded	O
into	O
G.726	B-Algorithm
in	O
1990	O
.	O
</s>
<s>
G.727	B-Algorithm
was	O
introduced	O
at	O
the	O
same	O
time	O
as	O
G.726	B-Algorithm
,	O
and	O
includes	O
the	O
same	O
bit	O
rates	O
,	O
but	O
is	O
optimized	O
for	O
packet	O
circuit	O
multiplex	O
equipment	O
(	O
PCME	O
)	O
environment	O
.	O
</s>
<s>
This	O
is	O
achieved	O
by	O
embedding	O
2-bit	O
quantizer	B-Algorithm
to	O
3-bit	O
quantizer	B-Algorithm
and	O
same	O
for	O
the	O
higher	O
modes	O
.	O
</s>
<s>
40kbit/s	O
G.726	B-Algorithm
can	O
carry	O
12000bit/s	O
and	O
slower	O
modem	B-Application
signals	O
,	O
while	O
32	O
kbit/s	O
G.726	B-Algorithm
can	O
carry	O
2400bit/s	O
and	O
slower	O
modem	B-Application
signals	O
well	O
and	O
4800bit/s	O
with	O
some	O
more	O
degradation	O
than	O
clear	O
channel	O
codecs	O
.	O
</s>
<s>
Since	O
the	O
byte	O
order	O
for	O
data	O
protocols	O
in	O
the	O
context	O
of	O
the	O
internet	O
was	O
generally	O
defined	O
as	O
big	O
endian	O
and	O
called	O
simply	O
network	O
byte	O
order	O
,	O
as	O
stated	O
(	O
among	O
others	O
)	O
by	O
the	O
deprecated	O
RFC	O
1700	O
,	O
the	O
deprecated	O
RFC	O
1890	O
did	O
not	O
explicitly	O
define	O
the	O
endianness	O
of	O
the	O
predecessor	O
of	O
G.726	B-Algorithm
,	O
G.721	B-Algorithm
,	O
in	O
RTP	O
either	O
.	O
</s>
<s>
The	O
payload	O
type	O
for	O
G.721	B-Algorithm
was	O
defined	O
by	O
the	O
deprecated	O
RFC	O
1890	O
as	O
2	O
,	O
thus	O
a	O
=	O
rtpmap:2	O
G721/8000	O
.	O
</s>
<s>
In	O
drafts	O
for	O
newer	O
version	O
of	O
this	O
RFC	O
,	O
it	O
was	O
reused	O
for	O
G.726	B-Algorithm
,	O
i.e.	O
</s>
<s>
a	O
=	O
rtpmap:2	O
G726-32/8000	O
.	O
</s>
<s>
Contrary	O
to	O
that	O
the	O
ITU	O
explicitly	O
defined	O
the	O
byte	O
order	O
in	O
its	O
recommendations	O
regarding	O
G.726	B-Algorithm
or	O
respectively	O
ADPCM	B-Algorithm
,	O
but	O
in	O
two	O
different	O
ways	O
.	O
</s>
<s>
Section	O
4.5.4	O
in	O
RFC	O
3551	O
defines	O
the	O
classical	O
MIME-types	O
G726-16	O
,	O
24	O
,	O
32	O
and	O
40	O
as	O
little	O
endian	O
and	O
introduces	O
new	O
MIME	O
types	O
for	O
bis	O
endian	O
,	O
which	O
are	O
AAL2-G726-16	O
,	O
24	O
,	O
32	O
and	O
40	O
.	O
</s>
<s>
Newer	O
implementations	O
respect	O
the	O
RFC	O
3551	O
and	O
clearly	O
distinct	O
between	O
G726-xx	O
(	O
little	O
endian	O
)	O
and	O
AAL2-G726-xx	O
(	O
big	O
endian	O
)	O
.	O
</s>
<s>
The	O
Gigaset	O
C610	O
IP	O
DECT	B-Protocol
phone	O
,	O
e.g.	O
,	O
generates	O
the	O
following	O
code	O
in	O
its	O
SIP	O
INVITE	O
:	O
</s>
