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