which  case  they  are  used  in  combination  with  a conjunctive   address   group.   Except   where   a geographical address group is required to complete the conjunctive  address  group,  geographical  address groups should not be used with the name of naval or merchant ships or the title of commands afloat. Address Indicating Groups An address indicating group (AIG) is a form of military   address   designator   representing   a predetermined list of specific and frequently recurring combinations of action and/or information addressees. The identity of the originator may also be included if the AIG is used frequently by any one originator. Each AIG is numbered so it will be easy to identify. An address group is assigned to each AIG for use as an address designator. AIG numbers may also be used as plain language address designators when appropriate. The purpose of AIGs is to increase the speed of traffic handling and to reduce the length of the address component.  Address  indicating  groups  can  be  used whenever suitable, regardless of whether the message concerned is unclassified or classified, unencrypted or encrypted, or in plaindress or codress form. Special Operating Groups Special operating groups comprised of four letters and identical in appearance with address groups are provided for use in the headings of messages to give special instructions. They are not to be used until a nation   or   service   has   promulgated   instructions authorizing their use. They must always be encrypted. They  may  be  used  singly,  or  with  encrypted  or unencrypted call signs or address groups. PLAIN LANGUAGE STATION AND ADDRESS DESIGNATORS Plain language address designators are the official abbreviated, or short titles, of commands or activities. They are used in message headings in place of call signs or address groups. Some abbreviated titles are written as single words, such as NAVSEA. Others have  conjunctive  titles  and  geographical  locations, such as NAVCOMMSTA PUERTO RICO. Plain language designators normally are confined to the abbreviated title of commands and activities listed  in  the  Standard  Navy  Distribution  List.  They may be used in communication with the U.S. Army, Air Force, and the armed forces of our Allies. They may not be used when addressing a message to a nonmilitary  activity,  in  the  heading  of  a  codress message, or in radiotelegraph messages originated by naval forces afloat. INCOMING MESSAGE PROCEDURE LEARNING  OBJECTIVE:  Discuss  the procedure   for   handling   and   distributing incoming and outgoing messages. The manner in which incoming messages are handled  and  distributed  aboard  ship  is  in  accordance with  stipulated  shipboard  communication  doctrine  or as  determined  otherwise  by  the  OOD.  Messages bearing a higher precedence than Routine receive particular attention, whether they are administrative or tactical in nature. There may be special procedures for Flash and Immediate visual traffic. In general, incoming nontactical messages are recorded on a message blank, shown to and initialed by   the   OOD,   and   delivered   promptly   to   the communications center for distribution. In the case of a  high-precedence  message,  however,  the  OOD usually orders the signal supervisor to have it shown immediately to the captain. If you are the signal supervisor, relay all tactical signals  to  both  the  OOD  and  CIC  (the  latter  by intercom, usually the 21MC circuit). The OOD or JOOD  refers  to  the  appropriate  signal  book  to interpret  the  signal's  meaning.  The  signal  is  also interpreted in CIC. The CIC watch officer informs the  OOD  of  its  meaning.  If  both  interpretations agree, the OOD will order you to indicate receipt for the message. There  are  excellent  reasons  for  requiring  two interpretations of each tactical signal. For one thing, the practice keeps CIC informed of the ship's possible movements. For another, there are many signals, particularly  for  maneuvering,  and  there  must  be  no error on the part of message addressees, because of the danger of collision. When OOD and CIC agree to the meaning  of  a  signal,  the  OOD  orders  the  signal acknowledged. On the rare occasion when there is disagreement, the OOD uses his or her judgment as to the  better  interpretation. SUMMARY In  this  chapter  you  learned  how  to  originate messages, and you became familiar with the many 3-17