<s>
Radio	O
over	O
Internet	B-Protocol
Protocol	I-Protocol
,	O
or	O
RoIP	B-Application
,	O
is	O
similar	O
to	O
Voice	B-Application
over	I-Application
IP	I-Application
(	O
VoIP	B-Application
)	O
,	O
but	O
augments	O
two-way	O
radio	O
communications	O
rather	O
than	O
telephone	O
calls	O
.	O
</s>
<s>
From	O
the	O
system	O
point	O
of	O
view	O
,	O
it	O
is	O
essentially	O
VoIP	B-Application
with	O
PTT	O
(	O
Push	O
To	O
Talk	O
)	O
.	O
</s>
<s>
With	O
RoIP	B-Application
,	O
at	O
least	O
one	O
node	O
of	O
a	O
network	O
is	O
a	O
radio	O
(	O
or	O
a	O
radio	O
with	O
an	O
IP	B-Protocol
interface	O
device	O
)	O
connected	O
via	O
IP	B-Protocol
to	O
other	O
nodes	O
in	O
the	O
radio	O
network	O
.	O
</s>
<s>
The	O
other	O
nodes	O
can	O
be	O
two-way	O
radios	O
,	O
but	O
could	O
also	O
be	O
dispatch	O
consoles	O
either	O
traditional	O
(	O
hardware	O
)	O
or	O
modern	O
(	O
software	O
on	O
a	O
PC	O
)	O
,	O
POTS	O
telephones	O
,	O
softphone	O
applications	O
running	O
on	O
a	O
computer	O
such	O
as	O
Skype	B-Application
phone	I-Application
,	O
PDA	B-Application
,	O
smartphone	B-Application
,	O
or	O
some	O
other	O
communications	O
device	O
accessible	O
over	O
IP	B-Protocol
.	O
</s>
<s>
RoIP	B-Application
can	O
be	O
deployed	O
over	O
private	O
networks	O
as	O
well	O
as	O
the	O
public	O
Internet	O
.	O
</s>
<s>
RoIP	B-Application
is	O
not	O
a	O
proprietary	O
or	O
protocol-limited	O
construct	O
but	O
a	O
basic	O
concept	O
that	O
has	O
been	O
implemented	O
in	O
a	O
number	O
of	O
ways	O
.	O
</s>
<s>
Several	O
systems	O
have	O
been	O
implemented	O
in	O
the	O
amateur	O
radio	O
community	O
such	O
as	O
Galaxy	O
PTT	O
Comms	O
,	O
AllStar	O
Link	O
,	O
BroadNet	O
,	O
IRLP	O
,	O
and	O
EchoLink	B-Protocol
that	O
have	O
demonstrated	O
the	O
utility	O
of	O
RoIP	B-Application
in	O
a	O
partly	O
or	O
entirely	O
open-source	O
environment	O
.	O
</s>
<s>
Many	O
commercial	O
radio	O
systems	O
vendors	O
such	O
as	O
Motorola	O
and	O
Harris	O
have	O
adopted	O
RoIP	B-Application
as	O
part	O
of	O
their	O
system	O
designs	O
.	O
</s>
<s>
The	O
motivation	O
to	O
deploy	O
RoIP	B-Application
technology	O
is	O
usually	O
driven	O
by	O
one	O
of	O
three	O
factors	O
:	O
first	O
,	O
the	O
need	O
to	O
span	O
large	O
geographic	O
areas	O
or	O
operate	O
in	O
areas	O
without	O
sufficient	O
coverage	O
from	O
radio	O
towers	O
;	O
second	O
,	O
the	O
desire	O
to	O
provide	O
more	O
reliable	O
,	O
or	O
at	O
least	O
more	O
repairable	O
links	O
in	O
radio	O
systems	O
;	O
and	O
third	O
,	O
to	O
support	O
the	O
use	O
of	O
many	O
base	O
station	O
users	O
,	O
that	O
is	O
,	O
voice	O
communications	O
from	O
stationary	O
users	O
rather	O
than	O
mobile	O
or	O
handheld	O
radios	O
.	O
</s>
<s>
Geographies	O
may	O
be	O
more	O
economically	O
reliably	O
served	O
when	O
spanned	O
by	O
the	O
use	O
of	O
IP	B-Protocol
technology	O
due	O
to	O
the	O
constantly	O
decreasing	O
cost	O
and	O
increasing	O
functionality	O
of	O
the	O
evolving	O
packet-switched	B-Protocol
network	I-Protocol
equipment	O
and	O
software	O
(	O
a	O
track	O
followed	O
by	O
Moore	O
's	O
law	O
)	O
.	O
</s>
<s>
Generally	O
,	O
the	O
cost	O
of	O
operating	O
a	O
radio	O
network	O
is	O
decreased	O
by	O
the	O
adoption	O
of	O
IP	B-Protocol
technology	O
,	O
replacing	O
the	O
traditional	O
microwave	O
and	O
leased	O
telephone	O
lines	O
.	O
</s>
<s>
Economical	O
and	O
reliable	O
distant	O
radio	O
links	O
such	O
as	O
those	O
needed	O
by	O
state	O
troopers	O
,	O
energy	O
utilities	O
,	O
and	O
Medivac	O
helicopters	O
are	O
well	O
served	O
by	O
RoIP	B-Application
technology	O
(	O
see	O
Air	O
Evac	O
Lifeteam	O
for	O
an	O
example	O
of	O
a	O
14-state	O
radio	O
system	O
)	O
.	O
</s>
<s>
The	O
conversion	O
to	O
RoIP	B-Application
also	O
drives	O
the	O
adoption	O
of	O
a	O
network	O
approach	O
rather	O
than	O
hub	O
and	O
spoke	O
architecture	O
that	O
is	O
typical	O
of	O
the	O
point-to-point	O
links	O
inherent	O
in	O
the	O
legacy	O
microwave	O
and	O
leased	O
line	O
technologies	O
.	O
</s>
<s>
equipped	O
when	O
the	O
radios	O
for	O
each	O
of	O
the	O
different	O
constituencies	O
are	O
made	O
available	O
in	O
the	O
center	O
via	O
RoIP	B-Application
at	O
each	O
user	O
's	O
computer	O
,	O
rather	O
than	O
via	O
a	O
handheld	O
radio	O
that	O
may	O
be	O
out	O
of	O
range	O
,	O
difficult	O
to	O
hear	O
,	O
and	O
out	O
of	O
batteries	O
throughout	O
the	O
emergency	O
.	O
</s>
<s>
Finally	O
,	O
RoIP	B-Application
by	O
its	O
nature	O
is	O
inter-operable	O
,	O
as	O
once	O
any	O
device	O
whether	O
radio	O
,	O
telephone	O
,	O
computer	O
,	O
or	O
PDA	B-Application
is	O
made	O
part	O
of	O
the	O
voice	O
network	O
enabled	O
by	O
IP	B-Protocol
,	O
it	O
is	O
irrelevant	O
what	O
type	O
of	O
technology	O
it	O
utilizes	O
.	O
</s>
<s>
RoIP	B-Application
systems	O
routinely	O
combine	O
VHF	B-Algorithm
,	O
UHF	O
,	O
POTS	O
telephone	O
,	O
Cellular	O
telephone	O
,	O
SATCOM	O
,	O
air-to-ground	O
,	O
and	O
other	O
technologies	O
into	O
a	O
single	O
voice	O
conversation	O
.	O
</s>
<s>
In	O
order	O
to	O
minimize	O
the	O
growth	O
of	O
Radio	B-Application
over	I-Application
IP	I-Application
technologies	O
that	O
are	O
incompatible	O
with	O
each	O
other	O
,	O
the	O
U.S.	O
Department	O
of	O
Homeland	O
Security	O
and	O
the	O
National	O
Institute	O
of	O
Standards	O
and	O
Technology	O
are	O
sponsoring	O
BSI	O
for	O
ROIP	B-Application
,	O
a	O
draft	O
standard	O
for	O
enabling	O
different	O
Radio	B-Application
over	I-Application
IP	I-Application
technologies	O
to	O
interoperate	O
.	O
</s>
<s>
Radio	O
Control	O
over	O
IP	B-Protocol
(	O
RCoIP	O
)	O
provides	O
the	O
essential	O
signaling	O
and	O
management	O
for	O
voice	O
messages	O
required	O
for	O
Critical	O
Communications	O
and	O
is	O
a	O
step	O
up	O
from	O
Radio	B-Application
over	I-Application
IP	I-Application
(	O
RoIP	B-Application
)	O
.	O
</s>
<s>
Catalyst	O
is	O
an	O
innovator	O
in	O
Radio	B-Application
over	I-Application
IP	I-Application
(	O
RoIP	B-Application
)	O
solutions	O
for	O
primary	O
dispatch	O
,	O
backup	O
dispatch	O
,	O
and	O
interoperability	O
.	O
</s>
<s>
is	O
a	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
software	O
program	O
designed	O
by	O
amateur	O
radio	O
enthusiasts	O
for	O
linking	O
amateur	O
radio	O
frequency	O
gateways	B-Application
and	O
repeaters	O
via	O
the	O
internet	O
by	O
using	O
a	O
Voice	B-Application
over	I-Application
IP	I-Application
protocol	O
.	O
</s>
<s>
It	O
is	O
developed	O
for	O
licence	O
free	O
radios	O
like	O
Citizens	B-Application
Band	I-Application
,	O
PMR446	O
and	O
Family	O
Radio	O
Service	O
.	O
</s>
