3.1 The principle features are:

• .1 use of a single frequency, with transmissions from stations within and between NAVAREAs and METAREAs co-ordinated on a time-sharing basis to reduce the risk of mutual interference. The following frequencies may be used for NAVTEX broadcasts:

  518 kHz
  Type of service:	International
  Content:	Maritime safety information
  Language:	English
  Co-ordination:	By IMO NAVTEX Co-ordinating Panel
  490 kHz and 4209·5 kHz
  Type of service:	National
  Content:	Maritime safety information
  Language:	As selected by the national administration
  Co-ordination:	Transmitter identification character allocated by IMO NAVTEX Co-ordinating Panel
  Other national frequencies allocated by the ITU
  Type of service:	National
  Content:	As selected by the national administration
  Language:	As selected by the national administration
  Co-ordination:	By appropriate national administration

• .2 a dedicated NAVTEX receiver, comprising radio receivers, a signal processor and either:

  • a) an integrated printing device; or

  • b) a dedicated display device with a printer output port and a non-volatile message memory; or

  • c) a connection to an integrated navigation system and a non-volatile message memory;

• which has the ability to select messages to be printed, or viewed and stored in a memory according to:

  • a) a technical code (B_lB₂B₃B₄), which appears in the preamble of each message; and

  • b) whether or not the particular message has already been printed/received;

  3.2 The operational and technical characteristics of the NAVTEX system are contained in Recommendation ITU-R M.540^footnote. Performance standards for shipborne equipment, if installed before 1 July 2005, are laid down in IMO Assembly resolution A.525(13). If installed on or after 1 July 2005, they should conform to IMO resolution MSC.148(77) ^footnote.