This example is a service message inviting attention (ZUI) to a previous service message with a reference number  of  0245.  Occasionally,  you  will  see  the acronym COSIR in a service message text, which means “Cite  Our  Service  in  Reply.”  Authorized  operating signals are used to the greatest extent possible in service messages,  but  clarity  must  not  be  sacrificed  for  brevity. The security classification is the first word of all service   message   text.   This   is   followed   by   the abbreviation “SVC.” If the service message requires special  handling,  the  special-handling  designator follows the security classification. For example: A service message may quote the textual content of a classified message or refer to the classified message in a manner that reveals textual content. In this case, the  service  message  must  be  assigned  the  same classification as the classified message being serviced. You can find detailed information on service messages in Automatic Digital Network (AUTODIN) Operating Procedures, JANAP 128. Tracer  Messages Tracer  messages  are  special  types  of  service message. Tracers are sent to determine the reason for excessive  delay  or  nondelivery  of  a  message  previously sent.  Normally,  tracer  requests  are  initiated  by  a message originator or addressee. However, a situation may  dictate  that  tracer  action  be  initiated  by  the originating  communications  station,  the  relay  station, or the communications station of the addressee. Tracer  action  continues  on  a  station-to-station  basis until  the  cause  of  delay  has  been  determined.  Upon receipt of a tracer, a station should examine its records for the time of receipt and transmission of the message being  traced.  This  information  is  compiled  and transmitted with the tracer action to the preceding station(s) and to the station that originated the tracer. The station that caused the delay or nondelivery must cite the reason and provide a summary of corrective action in the report. Tracer action requests must be initiated as soon as the discrepancy is discovered. Action must be initiated no  later  than  4  days  after  the  original  time  of transmission for a tactical addressee. For nontactical addressees, action must be initiated no later than 30 days from  the  original  time  of  transmission.  In-station records, files, logs, and tapes must be retained beyond the required retention limit if tracer action is in progress prior to the expiration date. You can find detailed information concerning tracer action in JANAP 128. Termination Request Messages Ships  send  termination  request  messages  to establish   circuits w i t h    a    N C T A M S    or NAVCOMTELSTA on a limited or full-time basis. A termination  request  message  must  be  sent  to  the cognizant NCTAMS at least 48 hours prior to activating the  requested  termination.  If  the  ship  has  a  requirement for a full-time termination, it will be assigned a routing indicator by the cognizant NCTAMS. NTP 4 contains detailed information pertaining to termination requests and  formats. Communications Guard Shift Messages Communications  guard  shift  (COMMSHIFT) messages are required when a command shifts its guard from  one  broadcast  or  servicing  communications  center to another. When possible, the shift takes effect at 0001Z of the new radio day. When broadcasts are shifted,  an  overlap  period  before  and  after  the  effective time is observed to ensure continuity of traffic. The command guards both broadcasts during the overlap period. COMMSHIFT messages are sent to the NCTAMS of the communication areas from which the old and the new broadcasts originate. COMMSHIFT messages are necessary because of operational considerations or changes in the deployment schedule of a ship. These messages are necessary when a command needs to effect a shift at a time other than that indicated by its movement  report.  Detailed  information  concerning communications guard shift messages and formats is contained in NTP 4. Broadcast Screen Requests Broadcast  screen  requests  (BSRs)  are  service messages to request the rerun (ZDK) of missed or garbled messages. BSRs are sent to the Broadcast Keying  Station  (BKS)  or  to  the  designated  broadcast screen ship that is responsible for the broadcast channel. NTP 4 provides detailed information and prescribes proper format for drafting a BSR. COMMSPOT Reports COMMSPOT reports are used to advise of any situation that might cause significant disruption of 2-24