All receivers are programmable to enable the user to ensure that only messages from selected CRSs are displayed/printed. Each CRS identifier from A to Z could be set in any of three modes:

• RECEIVE mode - messages are displayed/printed (accepted),
• IGNORE mode - messages are not displayed/printed (rejected),
• GPS (AUTO) mode - RECEIVE or IGNORE mode is automatically selected depending on vessel's position, but external navigational data like GPS is required.

NAVTEX receivers usually receive messages from any CRS by default. This situation is shown in the following interactive animation.

A vessel is indicated sailing within the Portpatrick NAVTEX CRS zone and towards the Malin Head NAVTEX CRS zone. NAVTEX CRS identifiers can be selected for reception on 518 kHz or 490 kHz as required. Initially all are accepted, that is, capital letters. Click on each of them to accept/reject as required. In the black field are listed basic information about received NAVTEX messages in scheduled transmission time regarding the set up of NAVTEX CRS identifiers and the CRS transmission range.

Because a vessel in the above interactive animation is sailing from Portpatrick CRS zone to Malin Head CRS zone it is suitable for that vessel to accept only messages with CRS identifiers O and Q on 518 kHz and optionally also messages with CRS identifier C on 490 kHz. Messages from all other CRS could be rejected because they have no relevance to the voyage.

Practise on the NAVTEX receiver simulator

Go to NAVTEX Mode -> Filter View -> 518 Stns Page or NAVTEX Mode -> Filter View -> 490 Stns Page.
NAVTEX receiver enables the use of 5 different filter settings, i.e. Presets 1 to 5. Active preset may be changed by pressing the PRESET softkey. Once a preset is selected, the filter settings for that preset may be changed as required. The filter setting for the active preset will be applied when NAVTEX messages are next viewed.

To change any setting navigate to it and press RIGHT/LEFT navigation key.

The filter value for each CRS identifier can be set to one of the following:

• On - messages from station always displayed,
• Off - messages from station never displayed,
• Auto - messages from station displayed only when nearest or in range depending upon Auto Station Filter setting.
  

The Auto Station Filter setting can be either:

• Nearest to display messages from the nearest station to your current position or
  
• In Range to display messages from all station in range of your current position.

An asterisk * appears next to all CRS identifiers for which messages will be displayed.