GMDSS: Element 3

1. A One-way communications to a single station, one-way communications to all stations, two-way communications.
2. B One-way communications to all stations, two-way communications, one-way communications to a single station.
3. C Two way communications, one-way communications to all stations, one-way communications to a single station.
4. D Two way communications, one-way communications to a single station, one-way communications to all stations.

Tip: press A-D to answer