Voice  Call  Signs Voice   call   signs   are   letters,   numbers,   or   a combination  of  letters  and  numbers  that  identify commands and units of commands. These include ships,   aircraft   squadrons   and   wings,   shore establishments,   type   commanders,   and   task organization components. The voice call signs change daily using the system that is in effect at the time of this writing. The Navy continues to strive to improve security and at the same time provide an efficient and workable system of call sign identification. Also available is JANAP 119, which contains ship and other joint armed forces voice call signs. Although the publication is always kept up to date, normally it is not used. JANAP 119 provides an adequate backup system, but lacks the security needed today. Visual Call Signs Visual call signs are primarily used for visual signaling. They are shorter than the other call signs or address  groups  assigned  to  an  organization.  This advantage is highly significant in determining the length of a flaghoist and reducing the transmission time of messages by other visual means. Visual call signs may be used (1) to establish communication  between  organizations,  (2)  in  the transmission  instructions  and  address  of  a  message that will be transmitted solely by visual means, and (3) for transmitting groups from authorized signal books, as follows: 1.   To  address ships, units, or commands, in which visual call signs precede the signals 2.   To complete, amplify, or vary the meaning of a signal, in which case visual call signs are used in conjunction  with  the  signal 3.   To denote or indicate ships, units, or commands in which case visual call signs follow the signal Visual   call   signs   will   not   be   used   in   the transmission instructions or address of a message to be transmitted or relayed by other than visual means. They may be used in the text when the text consists of signal groups. Visual call signs are as follows: 1.   Calls for ships 2.   Shortened visual calls 3.   Unit or command call signs 4.   Numeral pennant call signs 5. Special task organization call signs 6.  Signal  stations 7. Ships' boats 8.  Convoys In constructing visual calls to be transmitted by flaghoist,  numerals  are  expressed  by  numeral pennants except when numeral flags are specifically indicated. Numerals appearing in visual call signs transmitted by any visual means other than flaghoist represent numeral pennants and are written as pl, p5, p6, and so on, to distinguish them from numeral flags. By any visual means other than flaghoist, call signs are transmitted using the Morse code or semaphore equivalents.  All  call  signs  (except  radiotelephone)  in the text of signals from an authorized signal book are preceded by the special sign PT transmitted as a Morse or  semaphore  equivalent  meaning  “call  sign  to follow.” If more than one call sign appears in the text, each will be preceded by PT.  Call signs in the text may be spelled out when conditions make this advisable, spelled out call signs will also be preceded by PT. VISUAL CALLS FOR SHIPS.—Visual  call signs  for  ships  are  either  assigned  nationally  or constructed  using  the  appropriate  single-letter  type indicator plus the hull number of the ship. A list of single-letter type indicators follows: A   Auxiliary  (oiler,  cargo,  tender,  floating  drydock, B C D F G H K L M N P Q sloop, and so on.) Battleship Cruiser Destroyer/destroyer escort Frigate Government station Visual  signal  station  (military) Shore   signal   station   (commercial)   or miscellaneous  fleet  units  (NATO  use  only) Assault  vessel  (landing  craft,  amphibious transport dock, tank-landing ships, and so on.) Minesweeper Minelayer Fast  motor  craft  (submarine  chaser,  patrol escort, motor gunboat, motor torpedo boat, and so on.) Boat 3-12