Navtex cihazını şu mesajlarla beslemek gerekir
GPS
RMC - Konum
ZDA - Saat ve Tarih
Navtex cihazından şu mesajlar okunur
1. ALR - Set Alarm State
Cihazdaki alarm durumunu belirtir
Mesaj şöyle
1. Sentence Id2. Time of alarm condition change, UTC3. Unique alarm number (identifier) at alarm source4. Alarm's acknowledge state, A=Acknowledged,V=Unacknowledged5. Alarm condition, A=Threshold exceeded, V=Notexceeded6. Alarm description text
2. NRM - Navtex Receiver Mask Command
Mesaj şöyle. Hem input hem de output için kullanılabilir.
1. Sentence Id2. Function code, 0 to 93. Frequency table index, 1 to 94. Transmitter coverage area mask5. Message type mask6. Sentence status flag, R or C
3. NRX - Navtex Received Message
Açıklaması şöyle
The NRX sentence is used to transfer the contents of a received NAVTEX message from the NAVTEXreceiver to another device. As the length of a single NAVTEX message may exceed the number of characters permitted in a single NMEA 0183 sentence, many NRX sentences may be required to transfer a single NAVTEX message.
Mesaj şöyle
1. Sentence Id2. Total number of sentences, 001 to 9993. Sentence number, 001 to 9994. Sequential message id, 00 to 995. NAVTEX message code6. Frequency table index, 0 to 97. UTC of receipt of message8. Day, 1 to 319. Month, 1 to 1210. Year11. Total number of characters in this series of NRXsentences12. Total number of bad characters13. Status indication14. Message body
4. alan olan Sequential Message Id için açıklama şöyle. Aslında 5. alan olan NAVTEX message code alanının kullanılmaması söyleniyor. Bu alan cümleleri birleştirirken kullanılıyor.
The sequential message identifier provides a unique identifier for each NAVTEX message represented by a group of sentences.
Though the message code contains a NAVTEX message serial number, there are special cases when the message serial number is set to 00 and has a different meaning or when the same message code can occur more than once. When these conditions occur, the sequential message identifier can be relied upon to uniquely identify this NAVTEX message from other NAVTEX messages with the same message code.
6. alan olan Frequency Table Index için açıklama şöyle
The frequency indicator identifies the frequency that the NAVTEX message wasreceived on:0 = not received over air (eg test messages)1 = 490 kHz2 = 518 kHz3 = 4209,5 kHz4 through 9 are reserved for future use
14. alan olan message body "c - c Calculated" olarak işaretli. IEC 61162-1 Table 2'deki karakterlere göre çevrilmeli. Böylece her karakter için 1 byte harcanıyor
Örnek
Bir örnek şöyle. ^0D^0A "new line" demek. ^0A^0A mesaj sonu demek
The example below shows a typical message received by the Navtex receiver with 3 bad characters (‘*’):<start of example>ZCZC IE69==================================ISSUED ON SATURDAY 06 JANUARY 2001.INSHORE WATERS FORECAST TO 12 MILESOFFSHORE FROM 1700 UT* TO 0500 UTC.NORTH FORELAND TO SE**EY BILL.12 HOURS FORECAST:SHOWERY WINDS, STRONGEST IN NORTH.NNNN<end of example>Inspecting the corresponding NRX sentences would typically show:$CRNRX,007,001,00,IE69,1,135600,27,06,2001,241,3,A,==========================*09$CRNRX,007,002,00,,,,,,,,,,========^0D^0AISSUED ON SATURDAY 06 JANUARY 2001.*29$CRNRX,007,003,00,,,,,,,,,,^0D^0AINSHORE WATERS FORECAST TO 12 MILES^0D^0AOFF*0D$CRNRX,007,004,00,,,,,,,,,,SHORE FROM 1700 UT^2A TO 0500 UTC.^0D^0A^0D^0ANORT*70$CRNRX,007,005,00,,,,,,,,,,H FORELAND TO SE^2A^2AEY BILL.^0D^0A12 HOURS FOREC*16$CRNRX,007,006,00,,,,,,,,,,AST:^0D^0A^0ASHOWERY WINDS^2C STRONGEST IN NORTH.^0D*15$CRNRX,007,007,00,,,,,,,,,,^0A^0A*79Decoding the message body should give the following result:<start of decoding>==================================ISSUED ON SATURDAY 06 JANUARY 2001.INSHORE WATERS FORECAST TO 12 MILESOFFSHORE FROM 1700 UT* TO 0500 UTC.NORTH FORELAND TO SE**EY BILL.12 HOURS FORECAST:SHOWERY WINDS, STRONGEST IN NORTH.<end of decoding>
Aynı örnek şöyle
$CRNRX,007,001,00,TD02,1,135600,27,06,2001,241,3,A,==========================*09$CRNRX,007,002,00,,,,,,,,,,========^0D^0AISSUED ON SATURDAY 06 JANUARY 2001.*29$CRNRX,007,003,00,,,,,,,,,,^0D^0AINSHORE WATERS FORECAST TO 12 MILES^0D^0AOFF*0D$CRNRX,007,004,00,,,,,,,,,,SHORE FROM 1700 UTC TO 0500 UTC.^0D^0A^0D^0ANORT*70$CRNRX,007,005,00,,,,,,,,,,H FORELAND TO SELSEY BILL.^0D^0A12 HOURS FOREC*16$CRNRX,007,006,00,,,,,,,,,,AST:^0D^0A^0ASHOWERY WINDS, STRONGEST IN NORTH.^0D*15$CRNRX,007,007,00,,,,,,,,,,^0A^0A*79
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