-System applications
System applications provide services that are necessary for operation of the ATN.
-Air-ground applications
The ATN shall be capable of supporting one or more of the following applications: a) ADS-C
b) CPDLC; and
c) FIS (including ATIS and METAR).
-Ground-ground applications
The ATN shall be capable of supporting the following applications: a) ATS interfacility data communication (AIDC); and
b) ATS message handling services applications (ATSMHS).