Joint Electronics Type Designation System (The “AN” System)


With the rapidly expanding use of radio, radar and other electronic equipment in World War II, the old Army and Navy systems were increasingly unsuited for the new requirements. Therefore, the Army and Navy introduced the new “Joint Army-Navy Nomenclature System”, also known as “Joint Communications-Electronics Nomenclature System”, or short as “AN System”. This was formally approved on 17 February 1943, although the first designation assignments were already made in late December 1942. The initial emphasis was on airborne radio and radar equipment, but the system was designed to be extendable and was soon extended to include other types of equipment. When the Air Force separated from the Army in 1947, it continued to use the system for its electronic equipment. The Coast Guard started to use the system from 16 August 1951 and the Army from 8 June 1953. In 1957, the system was formalized in MIL-STD-196 “Joint Electronics Type Designation System” (JETDS). The system has since been slightly revised and adapted to modern requirements, and the current version is MIL-STD-196E, released on 17 February 1998.

In a way similar to the older Army and Navy systems, JETDS distinguishes between complete systems and components. The US military uses detailed definitions of “Item Levels” from single “Parts” to complete “Systems”. JETDS does not designate parts and assemblies, and uses different designation schemes for the other item types.

Sets And Systems

Sets, subsystems and systems are designated by the well-known “AN” nomenclature.

Examples: AN / A P G 5 A
AN / A L Q 151 (V)2
(1) (2) (3) (4) (5) (6)

All designations are prefixed by “AN/”. Originally, this stood for “Army-Navy”, but this interpretation is no longer valid. Nowadays, “AN/” is simply an indicator for the JETDS. In non-official references to electronic equipment, the “AN/” prefix is often omitted.

Letter (1) indicates the installation location of the equipment:

  • A – Piloted Aircraft
  • B – Underwater, Mobile (submarine)
  • C – Cryptographic Equipment (see note 1, note 2)
  • (C – Air Transportable; this installation indicator has been removed from the system)
  • D – Pilotless Carrier (missile, drone, UAV)
  • F – Ground, Fixed
  • G – Ground, General (multiple types of ground installation; see note 3)
  • K – Amphibious
  • M – Ground, Mobile (see note 4)
  • P – Portable (by man)
  • S – Surface Ship
  • T – Ground, Transportable (see note 5)
  • U – General Utility or Combination (see note 6)
  • V – Ground, Vehicle (see note 4)
  • W – Water Surface/Underwater Combination
  • Z – Piloted/Pilotless Airborne Combination

Letter (2) is the type of the equipment:

  • A – Invisible Light, Heat Radiation (i.e. infrared)
  • B – Comsec (secure communications; see note 1)
  • (B – Pigeon (see note 7); this type indicator has been removed from the system)
  • C – Carrier (electronic wave or signal)
  • D – Radiac (Radioactivity Detection, Identification, and Computation)
  • E – Laser (see note 8)
  • (E – NUPAC (Nuclear Protection & Control); this type indicator has been removed from the system)
  • F – Fiber Optics
  • (F – Photographic; this type indicator has been removed from the system)
  • G – Telegraph or Teletype
  • I – Interphone and Public Address
  • J – Electromechanical
  • K – Telemetering
  • L – Countermeasures
  • M – Meteorological
  • N – Sound in Air
  • P – Radar
  • Q – Sonar and Underwater Sound
  • R – Radio
  • S – Special or Combination
  • T – Telephone (Wire)
  • V – Visual, Visible Light
  • W – Armament (only used, if no other letter applies)
  • X – Fax or Television
  • Y – Data Processing
  • Z – Communications (see note 1)

Letter (3) defines the purpose of the equipment:

  • A – Auxiliary Assembly
  • B – Bombing
  • C – Communications
  • D – Direction Finding, Reconnaissance and Surveillance
  • E – Ejection and/or Release
  • G – Fire Control or Searchlight Directing
  • H – Recording and/or Reproducing
  • K – Computing
  • (L – Searchlight Control; this purpose indicator has been removed from the system; purpose now covered by “G”)
  • M – Maintenance or Test
  • N – Navigation Aid
  • (P – Reproducing; this purpose indicator has been removed from the system; purpose now covered by “H”)
  • Q – Special or Combination
  • R – Receiving or Passive Detecting
  • S – Detecting, Range and Bearing, Search
  • T – Transmitting
  • W – Automatic Flight or Remote Control
  • X – Identification or Recognition
  • Y – Surveillance (target detecting and tracking) and Control (fire control and/or air control)
  • Z – Secure (see note 1)

(4) is the model number. Each Installation-Type-Purpose letter combination uses its own model number sequence, starting at 1. Blocks of high model numbers are reserved for use by Canada (500-599, 2500-2599), Australia (2000-2099), New Zealand (2100-2199) and the UK (2200-2299). It seems that the first number of the Canadian block (500) is never used, i.e. Canadian designations always start with 501.

The optional suffix letter (5) denotes a specific version of the equipment. The first version uses no suffix, the first modifcation uses “A”, etc. The letters “I”, “O”, “Q”, “S”, “T”, “X”, “Y”, “Z” are not used as version suffix. “I”, “O”, “Q” and “S” could be confused with numerals 1, 0 and 5 respectively, for “T”, “X”, “Y” and “Z” see section 3.4.

(6) The “(V)” symbol indicates an equipment with variable components (sets, groups or units). A number following the “(V)” is used to designate a specific version of the equipment, i.e. with a specific component configuration. If a component of a set or system is of variable configuration, i.e. carries a “(V)” symbol, the set or system itself must also use the “(V)” symbol.


1. Installation letter “C”, type letters “B” and “Z”, and purpose letter “Z” are reserved for use by the NSA (National Security Agency) only.

2. “Cryptographic” is not an “installation” letter in the proper sense. It should have been a new “type” or “purpose” letter.

3. Installation letter “G” is used, when two or more of “F”, “M”, “P”, “T” or “V” apply.

4. Installation letter “M” is only used if the vehicle housing the equipment is solely designed for this purpose, i.e. the vehicle is a part of the equipment. For equipment installed in other vehicles, like tanks, etc., installation letter “V” is used.

5. Installation letter “T” is only used, if none of “G”, “M”, “P”, “U” or “V” can be applied. It is intended for equipment, which can be moved, but can’t be operated while in motion.

6. Installaton letter “U” is used in following two principally different cases:
– Equipment items (e.g. a radio AN/URC-n), which can be used in different installations (e.g. in aircraft, ship or ground installations)
– Systems, which consist of several components installed in different locations (e.g. the AN/USD-9 system has an airborne component AN/ARW-83 and a ground-based component AN/TSQ-105)

7. This designator was actually used. For example, the AN/CBQ-1 was an air-transportable pigeon loft & message center. The “AN” system, as originally devised, was intended for electronic and communications equipment. The US military used homing pigeons (on a small scale, of course) through WW II (the Army did not retire its last homing pigeon until 1957).

8. Type letter “E” (Laser) is a fairly recent (1985) addition to the system and is not in wide use. Most laser devices use either “V” or “A”, depending on the laser wavelength.


Source: Designation-Systems.Net