TRANSMISSION  ID  AND  CLASSIFICA- TION.—This data identifies the sending and receiving station routing indicators, and the message sequence number. This   data   is   usually   added   by   the telecommunications  center  entering  the  message  into NAVCOMPARS, or by the ships communications office. The third group of the top line indicates the Julian date and time of transmission. The fourth group indicates  the  classification  level.  The  second  line  of  the header is also a classification indicator. PRECEDENCE AND DTG.—A   single   letter identifies  the  message  precedence,  which  is  the message delivery time objective. Z (flash) means as fast as possible with an objective of less than 10 minutes, O (immediate) 30 minutes, P (priority) 3 hours, and R (routine) 6 hours. The date-time group is normally the UTC date (two digits), time (four digits), three-letter month abbreviation, and two-digit year that the message was released by the originating command. The times 0000Z and 2400Z are not used. Instead, use 0001Z or 2359Z. Keep in mind that certain METOC- related messages must be assigned specific precedence codes. This information can be found in the  United States  Navy  Meteorological  and  Oceanographic Support System Manual, NAVMETOCCOMINST 3140.1. ORIGINATOR.—After the FM designator, the command that originated the message is indicated by a Plain  Language  Address  (PLA)  listing,  followed  by  the originating office code set-off within double slants. ADDRESSEE. —The TO portion of the header identifies by PLA, specific commands that must act on the information contained within the message. Instead of, or in addition to, specific commands, the message may be addressed to one or more Collective Address Designators  (CADS),  or  Address  Indicating  Groups (AIGs). CADS are made up of predetermined lists of commands or communities of like interest. CADS may be  as  encompassing  as  ALCOM,  a  CAD  for  all commands (general messages), or limited to just several commands, such as OCEANO EAST, used to send weather observation from ships in the Atlantic Fleet to the  Naval  Atlantic  Meteorology  and  Oceanography Center in Norfolk and to FNMOC in Monterey. CAD listings for various types of METOC-related messages are listed in NAVMETOCCOMINST 3140.1. An  AIG  is  defined  as  an  address  designator representing a list of specific and frequently recurring combination of ACTION and/or INFORMATION addresses. For example, AIG 76 is used by FNMOC to send message traffic to certain activities concerning administrative and operational information, as well as notification of outages. Most of the PLAs and CADs used within the Department of Defense are listed by the Distributed Plain Language Address Verification System (DPVS). The purpose of DPVS is to provide naval message originators immediate electronic access to current single and collective PLA information. It is designed primarily to be used with the MTF Editor message preparation  program.  Updates  are  sent  via  BBS, Internet, and record message. INFO ADDEE.—The INFO portion of the header identifies PLAs of commands who need the information provided  in  the  message  for  information  purposes  only; no action is required on their part. EXEMPT  LISTING.—If  a  command  normally included  in  a  CAD  should  not  receive  a  specific message, an exempt listing must be included in the message header immediately following the last action or info addressee. The exempt listing is identified by the  abbreviation  XMT.  The  PLA  for  the  exempt command follows the XMT. TEXT SEPARATOR.—The text separator is the letters  BT.  This  indicates  the  separation  or  break between the heading and the body of a message. CLASSIFICATION  AND  SSIC.—Although actually apart of the message body, we will consider the classification and SSIC line to be part of the message header since this line must be included in all AUTODIN messages. The classification and SSIC line uses an identical style in all of the various message formats. The message classification is entered on a message by the  classification  word  plus  any  special  handling instructions. The classification is entered either as UNCLAS,   CONFIDENTIAL,   SECRET,   or   as TOP SECRET, with each letter separated by a space. After  the  last  special  handling  instructions,  the  Standard Subject   Identification   Code   (SSIC)   is   entered, bracketed by double slants. For example, //N03145// is the  SSIC  for  Enroute  Weather  Forecast  (WEAX) messages. SSIC codes are found in Department of the Navy File Maintenance Procedures and Standard Subject  Identification  Codes  (SSIC,),  SECNAVINST 5210.11. USMTF GENADMIN Message Body The   GENADMIN   format   is   used   for   all administrative  traffic  and  most  outgoing  weather forecast products. Terminal aerodrome forecast (TAF) messages also follow this format when transmitted via 1-22