<s>
Multimedia	B-Device
Home	I-Device
Platform	I-Device
(	O
DVB-MHP	B-Device
)	O
is	O
an	O
open	O
middleware	B-General_Concept
system	O
standard	O
designed	O
by	O
the	O
DVB	B-Application
project	I-Application
for	O
interactive	O
digital	O
television	O
.	O
</s>
<s>
The	O
MHP	O
enables	O
the	O
reception	O
and	O
execution	O
of	O
interactive	O
,	O
Java-based	O
applications	O
on	O
a	O
TV-set	O
.	O
</s>
<s>
MHP	O
applications	O
can	O
use	O
an	O
additional	O
return	O
channel	O
that	O
has	O
to	O
support	O
IP	B-Protocol
.	O
</s>
<s>
In	O
May	O
2010	O
the	O
largest	O
deployments	O
DVB-MHP	B-Device
are	O
in	O
Italy	O
(	O
DVB-T	O
)	O
,	O
Korea	O
(	O
DVB-S	O
)	O
,	O
Belgium	O
(	O
DVB-C	B-Device
)	O
and	O
Poland	O
(	O
DVB-S	O
)	O
with	O
trials	O
or	O
small	O
deployments	O
in	O
Germany	O
,	O
Spain	O
,	O
Austria	O
,	O
Colombia	O
,	O
Uruguay	O
and	O
Australia	O
.	O
</s>
<s>
The	O
U.S.	O
cable	O
industry	O
has	O
specified	O
its	O
own	O
middleware	B-General_Concept
system	O
referred	O
as	O
OCAP	B-Device
,	O
which	O
is	O
largely	O
based	O
on	O
MHP	O
.	O
</s>
<s>
Currently	O
,	O
Belgium	O
's	O
largest	O
cable	O
provider	O
Telenet	O
is	O
rolling	O
out	O
their	O
DVB-MHP	B-Device
system	O
,	O
called	O
DigiBox	O
.	O
</s>
<s>
Norway	O
's	O
upcoming	O
terrestrial	O
digital	O
TV	O
network	O
NTV	O
will	O
also	O
use	O
the	O
DVB-MHP	B-Device
standard	O
.	O
</s>
<s>
In	O
late	O
2008	O
the	O
Info+	O
channel	O
in	O
Greece	O
(	O
part	O
of	O
the	O
ERT	O
Digital	O
platform	O
)	O
started	O
broadcasting	O
DVB-MHP	B-Device
info	O
,	O
however	O
since	O
standards	O
have	O
not	O
been	O
set	O
as	O
of	O
February	O
2009	O
for	O
digital	O
television	O
in	O
Greece	O
,	O
most	O
TV	O
sets	O
and	O
DVB-T	O
receivers	O
sold	O
in	O
the	O
country	O
do	O
not	O
feature	O
DVB-MHP	B-Device
.	O
</s>
<s>
This	O
execution	O
environment	O
is	O
based	O
on	O
the	O
use	O
of	O
a	O
Java	B-Language
virtual	B-Architecture
machine	I-Architecture
and	O
the	O
definition	O
of	O
generic	O
APIs	B-General_Concept
that	O
provide	O
access	O
to	O
the	O
interactive	O
digital	O
TV	O
terminal	B-General_Concept
's	O
typical	O
resources	O
and	O
facilities	O
.	O
</s>
<s>
The	O
interoperable	O
MHP	O
applications	O
are	O
running	O
on	O
top	O
of	O
these	O
APIs	B-General_Concept
.	O
</s>
<s>
A	O
so-called	O
Navigator-application	O
,	O
which	O
is	O
part	O
of	O
the	O
terminal	B-General_Concept
software	O
,	O
allows	O
the	O
user	O
the	O
access	O
to	O
all	O
MHP	O
applications	O
and	O
other	O
DVB	B-Application
services	O
(	O
like	O
TV	O
and	O
radio	O
)	O
.	O
</s>
<s>
Sometimes	O
Navigator	O
can	O
be	O
also	O
a	O
Java	B-Language
program	O
itself	O
but	O
that	O
is	O
not	O
a	O
requirement	O
.	O
</s>
<s>
The	O
MHP	O
is	O
just	O
a	O
part	O
of	O
a	O
family	O
of	O
specifications	O
,	O
which	O
all	O
base	O
on	O
the	O
Globally	B-Language
Executable	I-Language
MHP	I-Language
(	O
GEM	O
)	O
-Standard	O
,	O
which	O
was	O
defined	O
to	O
allow	O
the	O
worldwide	O
adoption	O
of	O
MHP	O
.	O
</s>
<s>
The	O
first	O
type	O
are	O
DVB-HTML	B-Device
applications	O
.	O
</s>
<s>
These	O
are	O
not	O
very	O
popular	O
,	O
partly	O
because	O
the	O
specification	O
for	O
DVB-HTML	B-Device
was	O
only	O
completed	O
with	O
MHP	O
1.1	O
,	O
and	O
partly	O
because	O
many	O
broadcasters	O
,	O
box	O
manufacturers	O
and	O
content	O
developers	O
find	O
it	O
too	O
complex	O
and	O
difficult	O
to	O
implement	O
.	O
</s>
<s>
DVB-HTML	B-Device
applications	O
are	O
a	O
set	O
of	O
HTML	B-Language
pages	O
that	O
are	O
broadcast	O
as	O
part	O
of	O
a	O
service	O
.	O
</s>
<s>
The	O
spec	O
is	O
based	O
around	O
a	O
modularized	O
version	O
of	O
XHTML	B-Language
1.1	O
,	O
and	O
also	O
includes	O
CSS	B-Language
2.0	I-Language
,	O
DOM	B-General_Concept
2.0	O
,	O
and	O
ECMAScript	B-Language
.	O
</s>
<s>
The	O
second	O
,	O
and	O
by	O
far	O
the	O
most	O
popular	O
flavour	O
is	O
DVB-J	O
(	O
DVB-Java	O
)	O
applications	O
.	O
</s>
<s>
These	O
are	O
written	O
in	O
Java	B-Language
using	O
the	O
MHP	O
API	B-General_Concept
set	O
and	O
consist	O
of	O
a	O
set	O
of	O
class	O
files	O
that	O
are	O
broadcast	O
with	O
a	O
service	O
.	O
</s>
<s>
DVB-Java	O
applications	O
are	O
known	O
as	O
"	O
Xlets	B-Language
"	O
.	O
</s>
<s>
These	O
are	O
a	O
concept	O
similar	O
to	O
applets	B-Language
for	O
Web	O
pages	O
that	O
has	O
been	O
introduced	O
by	O
Sun	O
in	O
the	O
JavaTV	B-Language
specification	O
.	O
</s>
<s>
Like	O
applets	B-Language
,	O
the	O
xlet	B-Language
interface	O
allows	O
an	O
external	O
source	O
(	O
the	O
application	O
manager	O
in	O
the	O
case	O
of	O
an	O
MHP	O
receiver	O
)	O
to	O
start	O
and	O
stop	O
an	O
application	O
.	O
</s>
<s>
The	O
MHP	O
set-top	O
boxes	O
may	O
provide	O
a	O
backchannel	B-Protocol
for	O
applications	O
that	O
wish	O
to	O
communicate	O
with	O
the	O
outside	O
world	O
,	O
for	O
example	O
a	O
voting	O
or	O
shopping	O
application	O
.	O
</s>
<s>
Typical	O
upstream	O
backchannels	B-Protocol
are	O
phone	O
line	O
or	O
broadband	B-General_Concept
Internet	O
connection	O
(	O
ADSL	O
,	O
or	O
56k	O
in	O
Italy	O
,	O
using	O
a	O
modem	O
included	O
in	O
the	O
set-top	O
box	O
)	O
.	O
</s>
<s>
DVB-RCT	B-Device
(	O
Return	O
Channel	O
Terrestrial	O
)	O
is	O
a	O
wireless	O
technology	O
utilizing	O
the	O
DVB	B-Application
infrastructure	O
.	O
</s>
<s>
If	O
return	O
channel	O
is	O
present	O
it	O
should	O
provide	O
IP	B-Protocol
with	O
TLS	B-Protocol
support	O
.	O
</s>
