user-oriented  numbering  and  indexing  system.  It meets the requirements of all systems commands for identifying,  referencing,  and  requisitioning  technical manuals and changes. The system also makes it easier to identify and order manuals for the operating forces and other users. It is compatible with automatic data processing (ADP) procedures. The  Application Guide and  Index.  OPNAV  N0000-00-IDX-000/TMINS, should be available in your technical library. By using this guide and index, you will be able to understand and use the TMINS. The  TMINS  assigns  each  technical  manual  a unique   identifying   alphanumeric   designation patterned  after  the  13-digit  National  Stock  Number (NSN); for example, A1-F18AA-NFM-500. It serves as  the  technical  manual  identification  number. Additionally, TMINS contains a provision for adding a  suffix  to  give  the  security  classification  and  other information considered important. TMINS  NUMBER  COMPOSITION.—The standard TMINS number (fig. 2- 17) is made up of two distinct parts separated by a slash (/). The first part of the TMINS is called the publication identifier (PI). It is the essential root of the number. The PI is always used, and it always has exactly 13 characters. The second part of the TMINS is called the suffix. It is an added field of up to 17 characters (including the  slash).  When  used,  it  gives  user-oriented information. The suffix is always used for classified manuals and separately bound unclassified portions of classified  technical  manuals.  The  suffix  for  both classified  and  unclassified  TMINS  may  also  supply the user with equipment designation, nomenclature, or model number. PUBLICATION  IDENTIFIER  (PI) COMPOSITION. —The  publication  identifier  (PI)  is made up of two major components: the hardware/subject identifier and the technical manual (TM) identifier. The first seven characters of the PI make  up  the  hardware/subject  identifier.  These characters identify the specific hardware (such as an aircraft)  or  subject  (such  as  an  airborne  weapons system) to which the technical manual applies. Once assigned, the project serial number (for example, SA-AN/APS-39A  radar  set)  will  represent  the  item throughout its life cycle. The first seven characters of the PI (fig. 2- 17) are divided into three groups. The first group, cognizant (COG), of the PI is a single  letter  that  tells  what  command  publishes  and updates the publication. For example, the COG is A for NAVAIRSYSCOM. The second group, standard subject classification code (SSCC), is a four-digit alphanumeric code that identifies the commodity or subject matter; for example, in figure 2-17, the 1 in 1F18 indicates aircraft or aviation. The F18 stands for the F/A-18 aircraft. The  third  group,  subject  serial  number  (SUBJ SERIAL), is a two-digit code (either numbers, letters, or both) that is assigned by the Naval Air Technical Services  Facility  (NAVAIRTECHSERVFAC)  for aeronautic  manuals.  It  differentiates  between  items assigned to a given SSCC series or subseries. In figure 2-17, the subject serial number AC stands for F/A-18 aircraft federal labs. The remaining six characters of the PI are called the   technical   manual   (TM)   identifier.   The   six Figure 2-17.—TMINS example (NAVAIR). 2-16