<s>
EchoLink	B-Protocol
is	O
a	O
computer-based	O
Amateur	O
Radio	O
system	O
distributed	O
free	O
of	O
charge	O
that	O
allows	O
radio	O
amateurs	O
to	O
communicate	O
with	O
other	O
amateur	O
radio	O
operators	O
using	O
Voice	B-Application
over	I-Application
IP	I-Application
(	O
VoIP	B-Application
)	O
technology	O
on	O
the	O
Internet	O
for	O
at	O
least	O
part	O
of	O
the	O
path	O
between	O
them	O
.	O
</s>
<s>
In	O
essence	O
it	O
is	O
the	O
same	O
as	O
other	O
VoIP	B-Application
applications	O
(	O
such	O
as	O
Skype	B-Application
)	O
,	O
but	O
with	O
the	O
unique	O
addition	O
of	O
the	O
ability	O
to	O
link	O
to	O
an	O
amateur	O
radio	O
station	O
's	O
transceiver	O
.	O
</s>
<s>
Thus	O
any	O
low-power	O
handheld	O
amateur	O
radio	O
transceiver	O
which	O
can	O
contact	O
a	O
local	O
EchoLink	B-Protocol
node	O
(	O
a	O
node	O
is	O
an	O
active	O
EchoLink	B-Protocol
station	O
with	O
a	O
transceiver	O
attached	O
)	O
can	O
then	O
use	O
the	O
Internet	O
connection	O
of	O
that	O
station	O
to	O
send	O
its	O
transmission	O
via	O
VoIP	B-Application
to	O
any	O
other	O
active	O
EchoLink	B-Protocol
node	O
,	O
worldwide	O
.	O
</s>
<s>
No	O
special	O
hardware	O
or	O
software	O
is	O
required	O
to	O
relay	O
a	O
transmission	O
via	O
an	O
EchoLink	B-Protocol
node	O
.	O
</s>
<s>
The	O
EchoLink	B-Protocol
system	O
requires	O
that	O
each	O
new	O
user	O
provide	O
positive	O
proof	O
of	O
license	O
and	O
identity	O
before	O
his	O
or	O
her	O
callsign	O
is	O
added	O
to	O
the	O
list	O
of	O
validated	O
users	O
.	O
</s>
<s>
The	O
software	O
is	O
written	O
to	O
run	O
on	O
32-bit	O
and	O
64-bit	O
versions	O
of	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
Another	O
edition	O
of	O
the	O
software	O
runs	O
on	O
Apple	O
mobile	O
devices	O
(	O
iPhone	B-Device
,	O
iPod	B-Device
touch	I-Device
,	O
and	O
iPad	B-Device
)	O
,	O
and	O
is	O
available	O
from	O
the	O
Apple	O
App	O
Store	O
.	O
</s>
<s>
Qtel	O
is	O
an	O
opensource	O
version	O
of	O
the	O
software	O
available	O
in	O
many	O
Linux	B-Application
repositories	O
.	O
</s>
<s>
An	O
Android	B-Application
version	O
is	O
available	O
on	O
Google	O
Play	O
and	O
several	O
other	O
Android	B-Application
app	O
repositories	O
.	O
</s>
<s>
Radio	O
amateurs	O
using	O
the	O
EchoLink	B-Protocol
software	O
can	O
operate	O
it	O
in	O
one	O
of	O
two	O
modes	O
:	O
</s>
<s>
If	O
they	O
have	O
an	O
Internet-connected	O
computer	O
,	O
they	O
can	O
use	O
the	O
computer	O
's	O
microphone	O
and	O
speakers	O
to	O
connect	O
to	O
(	O
or	O
through	O
-	O
see	O
below	O
)	O
other	O
EchoLink-enabled	O
computers	O
over	O
the	O
Internet	O
and	O
talk	O
to	O
the	O
amateur	O
at	O
the	O
other	O
end	O
.	O
</s>
<s>
This	O
entails	O
connecting	O
their	O
own	O
VHF	B-Algorithm
or	O
UHF	O
transceiver	O
to	O
their	O
Internet-connected	O
PC	O
with	O
a	O
simple	O
homemade	O
or	O
manufactured	O
radio-PC	O
digital	O
mode	O
interface	O
.	O
</s>
<s>
Doing	O
this	O
enables	O
another	O
radio	O
amateur	O
with	O
their	O
own	O
transceiver	O
,	O
who	O
is	O
within	O
radio	O
range	O
of	O
this	O
station	O
,	O
to	O
communicate	O
with	O
(	O
or	O
through	O
)	O
any	O
other	O
EchoLink-equipped	O
station	O
anywhere	O
in	O
the	O
world	O
.	O
</s>
<s>
This	O
is	O
the	O
unique	O
feature	O
of	O
EchoLink	B-Protocol
.	O
</s>
<s>
Radio	O
amateurs	O
without	O
the	O
EchoLink	B-Protocol
software	O
or	O
a	O
computer	O
connected	O
to	O
the	O
Internet	O
can	O
take	O
advantage	O
of	O
the	O
EchoLink	B-Protocol
network	O
if	O
they	O
are	O
within	O
radio	O
range	O
of	O
a	O
sysop	O
mode	O
EchoLink	B-Protocol
station	O
.	O
</s>
<s>
It	O
is	O
also	O
possible	O
to	O
link	O
a	O
sysop	O
mode	O
EchoLink	B-Protocol
station	O
to	O
a	O
local	O
repeater	O
,	O
further	O
enhancing	O
the	O
communication	O
possibilities	O
.	O
</s>
<s>
Editions	O
of	O
EchoLink	B-Protocol
are	O
also	O
available	O
for	O
two	O
of	O
the	O
major	O
smartphone	B-Application
platforms	O
.	O
</s>
<s>
In	O
February	O
2010	O
,	O
an	O
edition	O
of	O
EchoLink	B-Protocol
was	O
released	O
for	O
the	O
Apple	O
iPhone	B-Device
,	O
iPad	B-Device
,	O
and	O
iPod	B-Device
Touch	I-Device
on	O
the	O
App	O
Store	O
.	O
</s>
<s>
In	O
August	O
2010	O
,	O
an	O
edition	O
of	O
EchoLink	B-Protocol
was	O
released	O
for	O
the	O
Android	B-Application
platform	I-Application
,	O
and	O
is	O
now	O
available	O
in	O
the	O
Google	O
Play	O
Store	O
.	O
</s>
<s>
Both	O
the	O
iOS	O
and	O
Android	B-Application
editions	O
were	O
created	O
by	O
Jonathan	O
Taylor	O
(	O
K1RFD	O
)	O
,	O
the	O
author	O
of	O
the	O
original	O
Windows	O
edition	O
.	O
</s>
<s>
Open	B-Application
source	I-Application
software	I-Application
packages	O
that	O
are	O
largely	O
compatible	O
with	O
EchoLink	B-Protocol
are	O
available	O
for	O
Macintosh	B-Device
(	O
and	O
)	O
and	O
Linux	B-Application
(	O
echoLinux	O
or	O
SvxLink/Qtel	O
)	O
.	O
</s>
<s>
SvxLink	O
Server	O
is	O
an	O
alternative	O
implementation	O
for	O
Linux	B-Application
.	O
</s>
<s>
EchoIRLP	O
is	O
a	O
software	O
add	O
on	O
for	O
IRLP	O
which	O
enables	O
an	O
IRLP	O
node	O
to	O
operate	O
as	O
a	O
sysop	O
mode	O
EchoLink	B-Protocol
station	O
.	O
</s>
<s>
The	O
EchoLink	B-Protocol
software	O
,	O
which	O
is	O
designed	O
to	O
run	O
on	O
Microsoft	B-Application
Windows	I-Application
,	O
has	O
also	O
been	O
known	O
to	O
work	O
on	O
several	O
Linux	B-Application
builds	O
as	O
well	O
if	O
loaded	O
through	O
Wine	B-Application
.	O
</s>
