<s>
DO-219	B-Device
is	O
a	O
communications	O
standard	O
published	O
by	O
RTCA	O
,	O
Incorporated	O
.	O
</s>
<s>
It	O
contains	O
Minimum	O
Operational	O
Performance	O
Standards	O
(	O
MOPS	O
)	O
for	O
aircraft	O
equipment	O
required	O
for	O
Air	B-Application
Traffic	I-Application
Control	I-Application
(	O
ATC	O
)	O
Two-Way	O
Data	O
Link	O
Communications	O
(	O
TWDL	O
)	O
services	O
.	O
</s>
<s>
TWDL	O
Services	O
are	O
one	O
element	O
of	O
Air	B-Application
Traffic	I-Application
Services	O
Communication	O
(	O
ATSC	O
)	O
.	O
</s>
<s>
The	O
Aeronautical	B-Device
Telecommunications	I-Device
Network	I-Device
(	O
ATN	O
)	O
provides	O
the	O
media	O
and	O
protocols	O
to	O
conduct	O
data	O
link	O
Air	B-Application
Traffic	I-Application
Services	O
Communication	O
.	O
</s>
