<s>
Media	B-Protocol
Resource	I-Protocol
Control	I-Protocol
Protocol	I-Protocol
(	O
MRCP	O
)	O
is	O
a	O
communication	O
protocol	O
used	O
by	O
speech	O
servers	O
to	O
provide	O
various	O
services	O
(	O
such	O
as	O
speech	B-Application
recognition	I-Application
and	O
speech	B-Application
synthesis	I-Application
)	O
to	O
their	O
clients	O
.	O
</s>
<s>
MRCP	O
relies	O
on	O
another	O
protocol	O
,	O
such	O
as	O
Real	B-Protocol
Time	I-Protocol
Streaming	I-Protocol
Protocol	I-Protocol
(	O
RTSP	B-Protocol
)	O
or	O
Session	B-Application
Initiation	I-Application
Protocol	I-Application
(	O
SIP	B-Application
)	O
for	O
establishing	O
a	O
control	O
session	O
and	O
audio	O
streams	O
between	O
the	O
client	O
and	O
the	O
server	O
.	O
</s>
<s>
MRCP	O
uses	O
a	O
similar	O
style	O
of	O
clear-text	O
signaling	O
as	O
HTTP	B-Protocol
and	O
many	O
other	O
Internet	O
protocols	O
,	O
in	O
which	O
each	O
message	O
contains	O
3	O
sections	O
:	O
a	O
first-line	O
,	O
a	O
header	O
and	O
a	O
body	O
.	O
</s>
<s>
Like	O
HTTP	B-Protocol
,	O
MRCP	O
uses	O
a	O
request	O
(	O
usually	O
issued	O
by	O
the	O
client	O
)	O
and	O
response	O
model	O
.	O
</s>
<s>
For	O
example	O
,	O
an	O
MRCP	O
client	O
may	O
request	O
to	O
send	O
some	O
audio	O
data	O
for	O
processing	O
(	O
say	O
,	O
for	O
speech	B-Application
recognition	I-Application
)	O
,	O
to	O
which	O
the	O
server	O
could	O
respond	O
with	O
a	O
message	O
containing	O
a	O
suitable	O
port	B-Protocol
number	I-Protocol
to	O
send	O
the	O
data	O
,	O
since	O
MRCP	O
does	O
not	O
have	O
support	O
for	O
audio	O
data	O
specifically	O
as	O
this	O
would	O
have	O
to	O
be	O
handled	O
by	O
some	O
other	O
protocol	O
,	O
such	O
as	O
Real-time	B-Protocol
Transport	I-Protocol
Protocol	I-Protocol
(	O
RTP	O
)	O
.	O
</s>
<s>
Version	O
2	O
uses	O
SIP	B-Application
for	O
managing	O
sessions	O
and	O
audio	O
streams	O
between	O
the	O
server	O
and	O
the	O
clients	O
,	O
whereas	O
version	O
1	O
did	O
not	O
specify	O
the	O
underlying	O
protocol	O
.	O
</s>
<s>
MRCP	O
has	O
been	O
adopted	O
by	O
a	O
wide	O
range	O
of	O
commercial	O
speech	O
servers	O
,	O
such	O
as	O
Verbio	O
Technologies	O
,	O
,	O
Microsoft	B-Application
Speech	I-Application
Server	I-Application
,	O
LumenVox	O
Speech	O
Engine	O
,	O
ReadSpeaker	O
speechServer	B-Application
MRCP	O
,	O
Nuance	O
Recognizer	O
and	O
Vocalizer	O
,	O
Sestek	O
TTS	O
,	O
Sestek	O
Call	O
Steering	O
as	O
well	O
as	O
commercial	O
Interactive	O
Voice	O
Response	O
software	O
such	O
as	O
Blueworx	O
Voice	O
Response	O
..	O
</s>
