<s>
KA9Q	B-Protocol
,	O
also	O
called	O
KA9Q	B-Protocol
NOS	I-Protocol
or	O
simply	O
NOS	O
,	O
was	O
a	O
popular	O
early	O
implementation	O
of	O
TCP/IP	B-Protocol
and	O
associated	O
protocols	O
for	O
amateur	O
packet	B-Application
radio	I-Application
systems	I-Application
and	O
smaller	O
personal	B-Device
computers	I-Device
connected	O
via	O
serial	O
lines	O
.	O
</s>
<s>
It	O
was	O
named	O
after	O
the	O
amateur	O
radio	O
callsign	O
of	O
Phil	O
Karn	O
,	O
who	O
first	O
wrote	O
the	O
software	O
for	O
a	O
CP/M	B-Application
system	O
and	O
then	O
ported	O
it	O
to	O
DOS	B-Device
on	O
the	O
IBM	B-Device
PC	I-Device
.	O
</s>
<s>
As	O
the	O
KA9Q	B-Protocol
package	O
included	O
source	O
code	O
,	O
many	O
radio	O
amateurs	O
modified	O
it	O
,	O
so	O
many	O
different	O
versions	O
were	O
available	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
KA9Q	B-Protocol
was	O
later	O
maintained	O
by	O
Anthony	O
Frost	O
(	O
callsign	O
G8UDV	O
)	O
and	O
Adam	O
Goodfellow	O
.	O
</s>
<s>
It	O
was	O
ported	O
to	O
the	O
Acorn	B-Device
Archimedes	I-Device
by	O
Jonathan	O
Naylor	O
(	O
G4KLX	O
)	O
.	O
</s>
<s>
Most	O
modern	O
operating	O
systems	O
provide	O
a	O
built-in	O
implementation	O
of	O
TCP/IP	B-Protocol
protocol	I-Protocol
;	O
Linux	O
especially	O
includes	O
all	O
the	O
necessary	O
kernel	O
functions	O
and	O
support	O
utilities	O
for	O
TCP/IP	B-Protocol
over	O
amateur	O
radio	O
systems	O
,	O
as	O
well	O
as	O
basic	O
AX.25	B-Protocol
and	O
NET/ROM	O
functionality	O
.	O
</s>
<s>
KA9Q	B-Protocol
is	O
also	O
a	O
name	O
for	O
the	O
IP-over-IP	O
Tunneling	B-Protocol
protocol	I-Protocol
.	O
</s>
