Standard format of NAVTEX messages

The standard format of NAVTEX message:
Phasing signal > 10 second
ZCZC Start of message group
B1 B2 B3 B4 B1: Transmiter, B2: Subject indicator, B3 B4: Message number
Time of origin Optional

Message text
NNNN End of message
Idle signal aa……a > 2 seconds
End of emmission.

The Transmitter Identification Character (B1):
Transmitter identification character is a single unique identifier which is allocated to each transmiter. It is used to identify the broadcasts which are to be accepted by the receiver and those which are to be rejected, and also the time slot for transmission.

Subject Indicator Characters (B2)
Information is grouped by subject on the NAVTEX broadcast and each subject group is allocated a subject indicator character.
The subject Indicator character is used by receiverr to identify different classes of message. the Indicator is also used to reject messages which aren’t required by theVessel. Receivers also use the B2 character to identify message which, because of their importance may not be rejected.
The following subject indicator Characters from A to Z are in use :
A = Navigational Warnings (can’t be rejected by the receiver)
B = Meteorologi Warnings (can’t be rejected by the receiver)
C = Ice Reports (found when we sailing in the cold area)
D = Search and Rescue information also pirate attack warnings (this also can’t be rejected by the receiver)
E = Meteorological Forecasts
F = Pilot Services Messages
G = AIS
H = LORAN Messages
I = Spare
J = SATNAV Message
K = Other Electronic Navaid Messages (concerning radio Navigation service)
L = Navigational Warning-additional to letter A (should not be rejected at the receiver (continuation of B2 subject group “A”))
V = Special services – allocation by NAVTEX Panel
W = Special services – allocation by NAVTEX Panel
X = Special services – allocation by NAVTEX Panel
Y = Special services – allocation by NAVTEX Panel
Z = No Message on hand

Message Numbering (B3 B4)
Each message within a subject group is allocated a serial number, B3 B4, between 01 and 99. This number will not necessarily relate to series numbering in other Radio Navigational Warning systems.
On reaching 99 will re-commence at 01 but avoiding the use of message number still in force.
A shortage of numbers will, where possible, be alleviated by the allocation of messages to other relevant subject groups. it has been found that 99 messages are not always enough for some subject groups, and B2 = L may be used for additional Navigational Warnings, to receive the overflow from B2 = A when necessary.

See the table bellow:

Common Abbreviations for International NAVTEX Services
Terminology in full	NAVTEX Abbreviations
Northeast or Northeasterly	NE
East or Easterly	E
SouthEast ShouthEasterly	SE
South or Sotherly	S
SouthWest or SouthWesterly	SW
West or Westerly	W
Northwestly or Northwestly	NW
Decreasing	DECR
Increasing	INCR
Variable	VRB
Becoming	BECMG
Locally	LOC
Moderate	MOD
Occasionally	OCNL
Scattered	SCT
Temporary / Temporarily	TEMPO
Isolated	ISOL
Frequent / Frequency	FRQ
Showers	SHWRS
Cold Front	C-FRONT / CFNT
Warm Form	W-FRONT / WFNT
Occlusion Front	O-FRONT / OFNT
Weakening	WKN
Building	BLDN
Filling	FLN
Deepening	DPN
Intensifiying / Intensify	INTSF
Improving / Improve	IMPR
Stationary	STNR
Quasi-Stationary	QSTNR
Move / Moving	MOV / MVG
Veering	VEER
Backing	BACK
Slowly	SLWY
Quickly	QCKY
Rapidly	RPDI
Knots	KT
Km / h	KMH
Nautical Miles	NM
Metres	M
HectoPascal	HPA
Meteo..	MET
Forecast	FCST
Further Outlooks	TEND
Visibility	VIS
Slight	SLGT or SLT
Quadrant	QUAD
Possible	POSS
Probable	PROB
Significant	SIG
No Change	NC
No Sinificant	NOSIG
Following	FWL
Next	NXT
Heavy	HVY
Severe	SEV / SVR
Strong	STRG
From	FM
Expected	Exp
Latitude / Longitude	LAT / Long