AN-/Citable Version

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Due to technical limitations, this article uses an unusual title. It should be called  AN/ prefix.

Most U.S. military electronics equipment has designations in the form AN/ABC-99, in which AN/ (note slash) is purely an identification for a designation system, not an abbreviation. This always-evolving system began as the Joint (Army-Navy) Electronics Type Designation System. Information security equipment under the control of the National Security Agency belongs to the TSEC/XYZ series, except certain of the letters in the AN/ system are reserved for NSA use.

While the designation system codes are quite complex and still contain special cases, the basic structure is:

  • First letter: Where or how is it installed?
  • Second letter: What kind of information or energy does it handle?
  • Third letter: What does it do with the information or energy?

The next numbers indicate a main model number within the series, followed by a bewildering and inconsistent set of version levels, alternate configurations, etc. Sometimes, what may seem an incremental improvement gets an entirely new model number, while a radical change may get a version change only. In other words, grasp the general principles of the system, but know that you will have to examine a specific system to understand its designation nuances.

So, in each of the following three systems, the differences are in the first letter, which tells the kind of platform (aircraft, ship, ground-transportable) that carries it.

The P in the second position means they radar energy, while the Y in the third position shows that they are combined target tracking and weapons fire control system. "Fire control" does not mean that the system is the only radar involved in guiding weapons for the application of the system; the three systems here are for long-range detection, and either guiding weapons-launching aircraft to the target or directing the initial flight of missiles. For example, the AN/SPY-2 detects a target, guides a RIM-156 Standard SM-2 missile to it, but, for the final attack of the missile, an AN/SPG-62 radar "illuminates" the target with energy that will be detected by the terminal guidance radar receiver inside the missile. See the specific AN/SPY-2, RIM-156 Standard SM-2, and AN/SPG-62 articles for further detail.

A somewhat more complex example, AN/APG-63 (V)3 is the airborne radar in the F-15 Eagle fighter.

  • A in the first position means airborne
  • P in the second position means radar
  • G in the third position, in this case, means weapons control
  • The first suffix part, (V) not only shows that it is a new version, but the (V) means it has a modular configuration, which can be changed in the field.
  • Following the (V), the 4 is a version number. As a practical demonstration that the number following the three letter code can be fairly arbitrary, the AN/APG-63 (V)4 not only replaces the (V)3 on the air superiority F-15, it also replaces the AN/APG-70 on the ground attack F-15E Strike Eagle.

In contrast, a simple letter suffix means that the system is not field reconfigurable.

Designation system codes

In the table below, only current codes are used. Animal-carried systems are no longer designated: the air-transportable pigeon loft and message center is no longer in service.

RR types in current use
Letter Installation Information Function
A Manned aircraft Invisible Light, Heat Radiation[1] Auxiliary equipment
B Submarine (formerly pigeon) Bombing
C NSA reserved Electronic carrier wave Communications
D Pilotless aircraft (UAV, drone) Ionizing radiation Direction finding, surveillance
E - Laser Ejection
F Fixed ground installation Fiber optics -
G Ground mobile Teletype or telegraph Fire (i.e., controlling the firing of weapons) or searchlight control
H - - Recording
I - Intercom, interphone, public address -
J - Electromechanical -
K Amphibious Telemetry Computing
L - Countermeasures -
M Self-propelled ground Meteorological Maintenance
N - Sound in air Navigation
O - - -
P Portable (personal) Radar -
Q - Underwater sound[2] Special
R - Radio Receiving or passive detecting
S Ship Special Active detecting, search
T Ground transportable; not usable while moving Telephone Transmitting
U Utility/combination - -
V Vehicle Visible light -
W Water Miscellaneous weapons Remote control
X - Television or facsimile Identification or recognition
Y - Computing Target tracking, fire control[3]
Z NSA reserved Secure (NSA reserved) NSA reserved

AN/ designations and system architecture

Various pieces of equipment, which have AN/ designations, are best understood when it is realized that they fit into larger architectures, or transitions between architectural generations. For example, there is an obsolescent tactical communications architecture called TRI-TAC, which, loosely speaking, is being replaced by Warfighter Information Network–Tactical (WIN-T).[4] Two major components of TRI-TAC are the AN/TTC-39 and Mobile Subscriber Equipment switches; the latter, for administrative reasons, does not have a full AN- designation. Some individual pieces of equipment, such as the AN/TTC-56 switch, are transitional between architectures such as TRI-TAC and full WIN-T.

Examine, however, the AN/TTC-39 designation. Its initial "T" indicates a transportable system that has to stop to operate. This specific piece of equipment requires large aircraft and trucks to transport. The second "T" shows that its major application is telephony. "C" in the third position shows that it is a communications system. The same prefix applies to the AN/TTC-56, but the implementation is quite different. The AN/TTC-56, for example, fits into intra-theater transport aircraft such as the C-130 Hercules, can be lifted by helicopter, or moved (with its electrical power generator) by a pair of HMMWV light wheeled utility vehicles.

These formal designations, in practice, are complemented by informal names. AN/TTC-39 switches, for example, are called "Tick 39", while the AN/TTC-56(V)1, officially the Single Shelter Switch, is called the triple-S by Army personnel.


  1. Could include ultraviolet
  2. May also include geophysical MASINT equipment that is not strictly sonar
  3. The "Y" suffix indicates longer-range tracking than "G", which tends to be for the final attack guidance only
  4. U.S. Army 2008 Posture Statement, Warfighter Information Network-Tactical