| Z | No message on hand |} Note: Receivers use the B2 character to identify messages which, because of their importance, can not be rejected (designated by a 1). The subject indicator characters B, F and G are normally not used in the United States since the National Weather Service normally includes meteorological warnings in forecast messages. Meteorological warnings are broadcast using the subject indicator character E. U.S. Coast Guard District Broadcast Notices to Mariners affecting ships outside the line of demarcation, and inside the line of demarcation in areas where deep draft vessels operate, use the subject indicator character A. Serial number of message (B3, B4) These two characters define the serial number of each B2 message type (class). Generally serial numbers start with the numbers '01', however in special circumstances, the numbers begin with '00'. This forces the receiver to print the message. Time of origin Time of origin is in the format of "DDHHmm UTC MMM YY" where DD is the date, HH hour, mm minute and MMM three-character abbreviation of month and YY year. The time of the transmission of the message is in UTC. Message text The full text of the message follows. End of message The end of the message is asserted when the characters "NNNN" are received. NAVTEX transmission schedule Each station identifier has a fixed 10-minute time slot, starting with A at 0000UTC. The time slots are repeated at 4 hour intervals. Within each time slot, a mix of navigation warnings, weather forecasts, ice information and other content may be sent, and this is normally according to a structured plan for that specific station. For example, in the first and third time slot they may decide to transmit navigation warnings, and weather forecasts in the others. Normally each NAVAREA or sub-NAVAREA has only one station at each slot. Details of all transmitting stations and their schedules may be found at NAVTEX receivers NAVTEX receivers which are approved for GMDSS contain an internal printer and/or a scrollable display, and cost between $800–$1500. A new generation of NAVTEX receivers intended for non-GMDSS applications such as the recreational community is entering the marketplace. These receivers include features such as LCD screens and RS-232 output and have a purchase price in the $300–$500 range. In the UK they can be purchased for £115. There are also a number of NAVTEX engines available that do not