| Name | Data Type | Definition | |
|---|---|---|---|
| UPLINK | string | Channel carries Ground-to-air traffic only. | |
| DOWNLINK | string | Channel carries Air-to-Ground traffic only. | |
| BIDIRECTIONAL | string | Channel carries traffic both ways. | |
| UPCAST | string | Broadcast from ground to aircraft. | |
| DOWNCAST | string | Broadcast from aircraft. | |
| OTHER | string | Other. |