The XOmail Maritime Gateway relays messages between domains connected via maritime communications and procedures. An XOmail Maritime Gateway is an XOmail Server with at least one Broadcast or Ship-Shore unit.

A number of Broadcast Units and Ship-Shore Units can be defined on an XOmail Maritime Gateway.

The Broadcast Unit handles the transmission (broadcasting) of messages to ships. The Ship-Shore Unit handles incoming messages from ships. Thus, two-way connectivity requires at least one Broadcast and one Ship-Shore Unit to be defined.

Broadcast Unit

The system offers two filtering functions for reducing broadcast load:

• Screening
  All messages are subject to automatic screening. Expired messages are discarded and suspected duplicates are halted.

• Vetting
  Messages may be stopped for manual review to determine the relevance in the current situation.

Other special Broadcast Unit functions are:

• Broadcast Schedules
  Ships may maintain reduced radio watch. A broadcast schedule can be established to ensure that messages are only sent during watch hours. Broadcast schedules can also be used for time-sharing a broadcaster, by allowing certain types of traffic (e.g. NATO only) during certain periods of the day.

• Automatic Re-runs
  To ensure that all called stations will receive a message, Re-runs of transmissions can be defined.

• Traffic Lists generation
  Broadcast Units log all broadcasted messages in Traffic Lists. The ship side uses these Traffic Lists to determine whether all broadcast messages are received or not.

Ship-Shore Unit

A Ship-Shore Unit handles incoming messages from ships. In addition, a Ship-Shore Unit provides functionality for automatic and manual aerial switching as well as reception quality assessment and control. A number of Ship-Shore Units can be defined on one XOmail Maritime Gateway.

The ship uses Working Channels for sending messages to the Maritime Gateway. A channel link must be established before a message can be sent. Channel establishment is either performed automatically using CARB procedures, or manually by an operator. In addition, an Aerial Select Channel can be used for directing/controlling the antenna used for receiving messages from ships.