reporting  are  contained  in  Allied  Maritime  Tactical Instructions and Procedures,  ATP 1, Volume I. There are two conditions under which enemy contact reports are to be made  more than once: When DO NOT ANSWER procedures are used (texts are transmitted twice in this procedure). When the text consists of emergency alarm signals. In this case, the text is transmitted twice, separated by the proword I SAY AGAIN, with a time group in the ending. When required, authentication is used in contact reports.  Lack  of  proper  authentication,  however,  should not prevent retransmission or relay of the message to higher  authority. There are two types of contact reports:  initial and amplifying.  As you would expect, initial reports are used  to  report  initial  contact  or  sightings.  These  reports should  be  sent  as  expeditiously  as  possible  with immediate,  pertinent  information  (type  vessel,  location, basic track, and so forth). The amplifying reports contain  all  necessary  amplifying  information  to  be  fully analyzed by higher authority or command. CODE AND CIPHER MESSAGES Code   words,   such   as   VERDIN   in   the   text EXECUTE PLAN VERDIN, are sent as plain language words. Encrypted groups, such as DRSRM, are spelled phonetically:  DELTA,  ROMEO,  SIERRA,  ROMEO, MIKE. The phonetic alphabet is used for the names of signal flags as well as for spelling words, letter groups, and so on. Signal flags are combined into code groups that  have  meanings  of  their  own.  DELTA  ROMEO ONE, for example, might mean “prepare to hover.” Signal flag A is ALFA, flag B is BRAVO, and so on. Meanings of such code groups are given in appropriate signal   publications. Because flag signals are also sent by R/T, you must be able to differentiate between the two uses of the phonetic letters when you hear them. Here is the way—if the phonetic alphabet is used, the proword I SPELL precedes it and each phonetic letter is recorded as a letter. If you hear I SPELL, followed by DELTA OSCAR, write it as DO.  On administrative nets, the proword  SIGNALS,  followed  by  DELTA  OSCAR, means the groups have been taken from a signal book and should be recorded as such. Prowords are not used on   nets   used   primarily   for   conveying   signals. Therefore, you may assume that alphabet flags are intended. The duties of an R/T operator require a knowledge of   the   special   language   developed   for   tactical maneuvering, air control, antiair warfare, naval gunfiie support,  electronic  countermeasures,  antisubmarine warfare, and other specialized uses. Words, phrases, and abbreviations used in R/T for these specialized uses are called operational brevity codes. A complete list of operational brevity code words is found in  Operational Brevity Codes, ACP 165. You should understand that the words and phrases of  the  brevity  code  provide  no  communications security. The purposes of the codes are to: Standardize the vocabulary; Improve the accuracy of the transmission; and Shorten transmission time. AUTHENTICATION Authentication is a security measure designed to protect  a  communications  system  against  fraudulent transmissions. There are specific times when you will have to use authentication procedures. Several types of authentication systems are in use, and the method of authentication will vary with the system that you are using.  Authentication  systems  are  accompanied  by specific instructions outlining the method of use. You can   find   more   information   about   the   types   of authentications and specific reasons when and why to use the authentication process in Communications Instructions—Security (U), ACP 122, and in NTP 5. COMMUNICATIONS CENTER ADMINISTRATION We will now show you some of the basic logs, command guard list (CGL), and changing call signs that deal  with  communications  center  administration. These short instructions are in no way a complete list of communications center operations. Each command has its own check-off lists or SOPs of how their command runs  its  center. CIRCUIT BACKLOGS Each circuit operator will notify the supervisor when the circuit status changes, when a backlog of traffic develops, when an outgoing transmission is delayed,  or  when  any  deviation  from  prescribed 1-20