Deck: Expired / Safety

1. A To ensure that a distressed vessel will have a "window" twice each hour for transmitting routine messages
2. B To ensure that interference on a particular frequency or channel to communications concerning emergency traffic is minimized
3. C To ensure that only voice communications can be effected on the distress frequency or channel
4. D To ensure that interference to proprietary communications is minimized

Tip: press A-D to answer