<s>
FX.25	O
is	O
a	O
protocol	O
extension	O
to	O
the	O
AX.25	B-Protocol
Link	O
Layer	O
Protocol	O
.	O
</s>
<s>
FX.25	O
provides	O
a	O
Forward	B-Error_Name
Error	I-Error_Name
Correction	I-Error_Name
(	O
FEC	O
)	O
capability	O
while	O
maintaining	O
legacy	O
compatibility	O
with	O
non-FEC	O
equipment	O
.	O
</s>
<s>
FX.25	O
is	O
intended	O
to	O
complement	O
the	O
AX.25	B-Protocol
protocol	O
,	O
not	O
replace	O
it	O
.	O
</s>
<s>
It	O
provides	O
an	O
encapsulation	O
mechanism	O
that	O
does	O
not	O
alter	O
the	O
AX.25	B-Protocol
data	O
or	O
functionalities	O
.	O
</s>
<s>
The	O
AX.25	B-Protocol
Link	O
Layer	O
Protocol	O
is	O
extensively	O
used	O
in	O
amateur	O
radio	O
communications	O
.	O
</s>
<s>
Consequently	O
,	O
AX.25	B-Protocol
links	O
are	O
inherently	O
intolerant	O
of	O
errors	O
.	O
</s>
<s>
The	O
FX.25	O
protocol	O
extension	O
provides	O
an	O
error	O
correction	O
"	O
wrapper	O
"	O
around	O
the	O
AX.25	B-Protocol
packet	O
,	O
allowing	O
for	O
removal	O
of	O
errors	O
at	O
the	O
receiving	O
end	O
.	O
</s>
<s>
Data	O
fields	O
have	O
been	O
carefully	O
chosen	O
to	O
allow	O
reception	O
of	O
the	O
AX.25	B-Protocol
packet	O
data	O
within	O
an	O
FX.25	O
frame	O
by	O
a	O
non-FEC	O
decoder	O
.	O
</s>
<s>
A	O
composite	O
FX.25	O
entity	O
is	O
called	O
a	O
"	O
frame	O
,	O
"	O
distinguishing	O
it	O
from	O
the	O
AX.25	B-Protocol
"	O
packet	O
"	O
contained	O
within	O
.	O
</s>
<s>
The	O
FEC	O
frame	O
currently	O
implements	O
Reed	B-Error_Name
Solomon	I-Error_Name
error	O
correction	O
algorithms	O
,	O
but	O
is	O
not	O
restricted	O
to	O
these	O
.	O
</s>
<s>
Performance	O
improvement	O
will	O
be	O
a	O
function	O
of	O
AX.25	B-Protocol
packet	O
size	O
combined	O
with	O
the	O
noise	O
characteristics	O
of	O
the	O
transmission	O
channel	O
.	O
</s>
