The Joint Electronics Type Designation System (JETDS), which was previously known as the Joint Army-Navy Nomenclature System (AN System. JAN) and the Joint Communications-Electronics Nomenclature System, is a method developed by the U.S. War Department during World War II for assigning an unclassified designator to electronic equipment. In 1957, the JETDS was formalized in MIL-STD-196.

Computer software and commercial unmodified electronics for which the manufacturer maintains design control are not covered.


Electronic material, from a military point of view, generally includes those electronic devices employed in data processing, detection and tracking (underwater, sea, land-based, air and space), recognition and identification, communications, aids to navigation, weapons control and evaluation, flight control, and electronics countermeasures. Nomenclature is assigned to:

This system is separate from the "M" designation used in the Army Nomenclature System (MIL-STD-1464A).


Items are given an Item Level which describes their hierarchy

Table i (MIL-STD-196G)[1]
Item Level Description Examples
Unit An item that may be capable of independent operation but whose functionality is not complete without other items. Installation and Maintenance kits are the only unit level items that may contain complement data. Radio, computer, digital Power Supply, Antenna or radio receiver.
Group A collection of units or assemblies that are not capable of performing a complete operational function. A group may be a subdivision of a set or may be designed to be added to or used in conjunction with a set to extend the function or the utility of the set. Antenna group may be “used with” or “part of” a radio set.
Set A unit or units and necessary assemblies, subassemblies and parts connected together or used in association to perform an operational function Radio terminal set or sound measuring set, including parts, assemblies and units such as cables, microphone and measuring instruments.
Subsystem A combination of sets, groups, etc., which performs an operational function within a system and is a major subdivision of the system. Intercept-Aerial Guided Missile Subsystem
System A combination of two or more sets, which may be physically separated when in operation, and such other assemblies, subassemblies and parts necessary to perform an operational function or functions. Integrated Shipboard Computer System and a Navigational Control System
Center A collection of units and items in one location, which provides facilities for the administrative control in an area of responsibility which is specifically assigned for development and maintenance of installations, control of personnel, or conduct of tactical operations an Operations Center
Central A grouping of sets, units or combinations thereof operated conjunctively in the same location for a common specific function. It may provide facilities for controlling switching, monitoring, etc., electronic and electrical equipment from one central location. Operations Central, Central, Communications

Basic Structure

The core of the JETDS system is the combination of a Type Designation with an Item Name to specify a particular item.

For example:

Type Designation

The type designation is a unique series of letters and numbers which specifies an item. There are three basic forms of type designator used:

Item Name

The Type Designation is used in conjunction with an approved Item Name drawn from the H-6 Item Name Directory.

For example:

Type Designation (Systems, Subsystems, Centers, Central, Sets)

The type designation used to specify Systems, Subsystems, Centers, Central, and Sets is made up of a prefix AN/, three type designation indicator letters, a hyphen, and a type designation number. The AN prefix signifies Army-Navy. The three type designation letters (chosen from the table below) specify where the equipment is used, what the equipment is, and what its purpose is. The type designation number helps specify the exact item; subsequent items with the same Installation/Type/Purpose are numbered sequentially (ie. the next item developed after the AN/PRC-34 would be the AN/PRC-35).

For example:

Table 1. Indicators for Systems/Subsystems/Centers/Central/Sets[1]
Installation (1st letter) Type of Equipment (2nd letter) Purpose (3rd letter) Miscellaneous
A - Piloted Aircraft (includes parachutes and piloted balloons) A - Invisible Light, Heat Radiation (e.g., infrared) A - Auxiliary Assembly X, Y, Z for changes in voltage, frequency, or phase
B - Underwater Mobile (submarine) B - Communications security (was Pigeon) (NSA use only) B - Bombing Tn for Training versions
C - Cryptographic Equipment (was Air, Transportable) (NSA use only) C - Carrier (electronic wave or signal) C - Communications (Receiving/Transmitting, two way) (C) NSA use only
D - Pilotless Carrier (UAV, missile, rocket) D - Radiac (Radioactivity Detection, Identification, and Computation) D - Direction Finder, Reconnaissance, and Surveillance (P) accepts plugins
E - Laser (was NUPAC: Nuclear Protection & Control) E - Ejection and/or Release (V) variable items
F - Ground, Fixed * F - Fiber Optics (was Photographic) (- FT, - IN) identical items with varying lengths
G - Ground, General * G - Telegraph or Teletype G - Fire Control or Search Light Directing ( ) developmental or experimental
H - Recording and/or Reproducing
I - Interphone and Public Address
J - Electromechanical or Inertial Wire Covered
K - Amphibious (vehicles) K - Telemetering K - Computing Automatic Digital Processing Equipment (ADPE)
L - Countermeasures L - removed (was Searchlight Control, now covered by "G") 1. Digital Equipment Only
M - Ground, Mobile * M - Meteorological M - Maintenance or Test Assemblies 2. Analog Equipment Only
N - Sound in Air N - Navigational Aids 3. Hybrid (1 & 2 combined)
4. Input/Output Device
P - Portable (ie. man-portable) P - Radar P - removed (was Reproducing, now covered by "H") 5. Magnetic Media
Q - Sonar and Underwater Sound Q - Special or Combination 6. Others
R - Radio R - Receiving or Passive Detecting
S - Water (surface ship or buoys) S - Special or Combination S - Detecting or Range and Bearing, Search
T - Ground, Transportable * T - Telephone (Wire) T - Transmitting
U - General Utility (multi use) *
V - Ground, Vehicle * V - Visual, Visible Light
W - Water Surface and Underwater combined * W - Armament (not otherwise covered) W - Automatic Flight or Remote Control
X - Facsimile or Television X - Identification and Recognition
Y - Data Processing or Computer Y - Surveillance (search, detect, and multiple target tracking) and Control (both fire control and/or air control)
Z - Piloted and Pilotless Airborne Vehicles combined * Z - Communications (NSA use only) Z - Secure (NSA use only)

* Additional info on Installation indicators:

** Additional info on Type of Equipment indicators:

Type Designation (Group)

The type designation used to specify Groups (assemblies that are used in conjunction with others to function) is made up of a two letter group indicator (from the table below), followed by a dash, a group number, followed by a slash, and 1-3 letters specifying the equipment it is "part of" or "used with" (see Table 1). If the group is unique and only "part of" or "used with" one particular equipment, that equipment may be specified. If the group may be used with multiple different items, then it is more appropriate to designate it more generally.

For example:

Table 2. Group Indicators[1]
Group Indicator Family Name Examples (does not limit the application of group indicators)
OA Miscellaneous groups Groups otherwise not listed. Do not use if a more specific group indicator applies
OB Multiplexer and/or demultiplexer groups All types
OD Indicator groups All types
OE Antenna groups All types
OF Adapter groups All types
OG Amplifier groups All types
OH Simulator groups All types
OI Cryptographic groups All types
OJ Consoles and Console groups All types
OK Control groups All types
OL Data analysis and Data processing groups All types
OM Modulator and/or Demodulator groups All types
ON Interconnecting groups All types
OP Power Supply groups All non-rotating types
OQ Test-Set groups All types
OR Receiver groups All types
OS Satellite groups All types
OT Transmitter groups All types
OU Converter groups All types
OV Generator groups All types including power generating equipment
OW Terminal groups Telegraphs, radios, telephones, etc.
OX Coder, Recorder, Interrogator, Transponder groups All types
OY Radar groups Do not use if more specific indicator applies
OZ Radio groups Do not use if a more specific indicator (OE, OR, OT, etc.) applies

Type Designation (Unit)

The type designation used to specify Units is made up of a unit letter(s) indicator (from the table below), followed by a dash, a unit number, followed by a slash, and 1-3 letters specifying the equipment it is part of or used with (see Table 1). As with Group type designations, if the Unit is unique and is "part of" or "used with" only one particular equipment, that equipment may be specified. If the unit is used with multiple different items, the equipment designation should include only the indicators which are common or appropriate. If a unit could be described by multiple indicators, the indicator which best describes the unit's primary function should be used. The exception would be if there exists a unit indicator which can describe the unit's multiple functions (see examples below); if such a multi-function describing unit indicator exists, then it should be used.

For example:

Table 3. Unit Indicators[1]
Unit Indicator Family Name Examples (does not limit the application of unit indicators)
AB Support for antennas Antenna mounts, mast bases, mast sections, towers, etc.
AM Amplifiers Power, audio, interphone, radio frequency, video, electronic control, etc.
AS Antennas, simple and complex Arrays, parabolic type, masthead whip or telescopic loop, dipole, reflector, etc.
BA Batteries, primary (non-rechargeable) type Batteries, battery packs, etc.
BB Batteries, secondary (rechargeable) type Batteries, battery packs, etc.
BZ Alarm units All types
C Controls Control boxes, remote tuning controls, etc.
CA Computer auxiliary units Input/Output, peripherals, etc.
CC Cable assemblies, RF RF cables, waveguides, transmission lines, etc., with terminals
CD Controlling devices Complex controlling devices
CM Comparators Compares two or more input signals
CN Compensators Electrical and/or mechanical compensating, regulating, or attenuating apparatus
CP Computers Mechanical and/or electronic mathematical calculating devices
CU Couplers Impedance coupling devices, directional couplers, etc.
CV Converters (electronic) Electronic apparatus for changing the phase frequency, or from “one” medium to “another”
CW Radomes Radomes
CX Cable assemblies, non-RF Non-RF cables with terminals, test leads, also composite cables of RF and non-RF conductors
CY Cases and cabinets Rigid and semi-rigid structures for enclosing or carrying equipment
D Dispensers Chaff
DA Loads, dummy RF and non-RF test loads
DI Data transmission units Devices for authentication and transferring recorded or generated data over transmitter/receiver links
DT Detecting heads Magnetic, capacitive, or optical pickup devices, search coils, hydrophones, etc.
DU Display Units/Monitors All types that are external devices for computers, test sets, etc.
F Filter units Electronic types, back-pass, low pass, band suppression, noise telephone, filter networks; excludes non-repairable types
FO Fiber optics Electrical, electronic, and communications, etc.
FR Frequency measuring devices Frequency meters, tuned cavity, etc.
G Generators, power Electrical power generators without prime movers (see PU)
GO Goniometers Instruments for measuring angles for determination of energy transferred from moving to fixed coil (directional) antennas, etc.
H Head, hand, and chest sets Includes earphones
HD Environmental apparatus Heating, cooling, dehumidifying, pressure, vacuum devices, etc.
ID Indiciator units, non-cathode ray tube Calibrated dials and meters, indicating lights, etc. (see also IP)
IM Intensity measuring devices Includes SWR gear, field intensity noise meters, slotted lines, etc.
IP Indicator units, cathode ray tube Azimuth, elevation, panoramic, etc.
J Interface units Interconnecting and junction units, etc. Do not use if a more specific indicator applies.
KG Key generators Units generating a pseudorandom sequence of crypto variables using algorithms
KY Keying devices Mechanical, electrical, and electronic key coders, interrupters, etc.
LA Lasers Communication, electrical, etc.
LS Loudspeakers Separately housed loudspeakers and intercommunication stations
M Microphones Radio, telephone, throat, hand, etc.
MD Modulators, demodulators, discriminators Devices for varying amplitude, frequency, or phase
ME Meters Multimeters, vacuum tube voltmeters, power meters, volt-ohm-milliameters, etc.
MK Miscellaneous kits Maintenance, modification, etc.
ML Meteorological devices Miscellaneous meteorological equipment, etc.
MO Multipurpose Units that perform two or more functions
MT Mountings Mountings, racks, frames, stands, etc.
MU Memory units Memory units
MW Microwave Communications, etc.
MX Miscellaneous Equipment not otherwise classified. Do not use if a better indicator is available
O Oscillators Master frequency, blocking, multi-vibrators, etc. (for test oscillators: see SG)
OC Oceanographic devices Bathythermograph, etc.
OS Oscilloscope, test Test oscilloscopes, for general test purposes (see IP)
PL Plug-in units Plug-in units not otherwise classified
PP Power supplies Non-rotating machine types such as vibrator pack, rectifier, thermoelectric, etc.
PT Mapping and plotting units Electronic types only
PU Power equipment Rotating power equipment, motor-generators, dynamotors, etc.
R Receivers Receivers, all types except telephone
RB Robotics Electric-mechanical, etc.
RD Recorder-Reproducers Sound, graphic, tape, wire, film, disc, facsimile, magnetic, mechanical, etc.
RE Relay assembly units Electrical, electronic, etc.
RL Reeling machines Mechanisms for dispensing and rewinding antenna or field wire cable, etc.
RO Recorders Sound, graphic, tape, wire, film, disc, facsimile, magnetic, mechanical, tape and card punch, etc.
RP Reproducers Sound, graphic, tape, wire, film, disc, facsimile, magnetic, mechanical, punched tape and card readers, etc.
RR Reflectors Target, confusion, etc., except antenna reflectors (see AS)
RT Receiver and Transmitter Radio and radar transceivers, composites of transmitter and receiver, etc.
S Shelter Protective shelters, etc.
SA Switching units Manual, impact, motor-driven, pressure-operated, electronic, etc.
SB Switchboards Telephone, fire control, power distribution, etc.
SG Generator, signal Test oscillators, noise generators, etc. (see O)
SM Simulators Flight, aircraft, target, signal, etc.
SN Synchronizers Equipment to coordinate two or more functions
SS Special purpose Devices performing unique functions
SU Optical units Electro-optical units, such as night vision, scopes, sights, auto-collimator, viewers, trackers, alignment equipment
SY Speech, secure Devices that secure voice transmission/receiving equipment
T Transmitters Transmitters, all types except telephone
TA Telephone apparatus Miscellaneous telephone equipment
TB Towed body Hydrodynamic enclosures used to house transducers, hydrophones, and other electronic equipment
TD Timing devices Mechanical and electronic timing devices, range devices, multiplexers, electronic gates, etc.
TF Transformers When used as separate units
TG Positioning devices Tilt and/or train assemblies
TH Telegraph apparatus Miscellaneous telegraph items
TN Tuning units Receiver, transmitter, antenna, tuning units, etc.
TR Transducers Sonar transducers, vibration pickups, etc. (see H, LS, and M)
TS Test units Test and measuring equipment not otherwise classified. Do not use if more specific indicators apply
TT Teletypewriter and facsimile apparatus Teletype, tape, facsimile miscellaneous equipment
TU Television Special types
TW Tape units Preprogrammed with operational test and checkout data
V Vehicles Carts, dollies, vans peculiar to electronic equipment
ZM Impedance measuring devices Used for measuring Q, C, L, R, or PF, etc.

Additional Specifiers

Modification Letter

A modification letter is placed after the type designation number to signify a modification to a specific equipment that still retains at least one-way interchangeability with all previous versions. Modification letters begin with "A" and proceed sequentially. For more information on Interchangeability (see below).

Note: the letters "I", "O", "Q", "S", "T", "X", "Y", and "Z" are not to be used as modification letters

For example:

Specific Configurations of Variables

A suffix "(V)" following the type designation number and any modification letters indicates variable components or configurations for said Group/Set/Subsystem/System/Center/Central. A number may follow the parenthetical V to identify a specific configuration.

For example:

Note: A specific equipment should only be given a (V) signifier if it can be configured with different components, not simply because one of its components has a (V) signifier. The (V) signifier would be warranted if the item accepted variable configurations of a particular component.

For example:

Plug-In (capable)

A suffix of "(P)" following the type designation number and any modification letters indicates a Unit which is designed to accept "plug-in" modules capable of changing the function, frequency, or other technical characteristics of the unit. The plug-in is not considered part of the unit itself.

For example:


A suffix of "(C)" following the type designation number and any modification letters indicates an item which directly contains NSA-controlled cryptographic material. See also: Classified information in the United States#Confidential.

For example:

Training (Set, Subsystem, System, Center, or Central)

A suffix of "-Tn ", where n is a number, indicates equipment (Set, Subsystem, System, Center, or Central) designed to provide training in the operation of a specific set or multiple sets. If it is designed specifically to provide training for one particular unit, then that unit may be specified. If it is a training equipment which can provide practice for various different sets/subsystems/systems etc., then that should be indicated with the appropriate letter indicators.

For example:

Training (Group or Unit)

For example:

Automated Data Processing Equipment (ADPE)

A digit or digits in parentheses following the type designation letters indicates the type of ADPE included in the item.

For example:

1 Digital Equipment Only
2 Analog Equipment Only
3 Hybrid (1 & 2 combined)
4 Input/Output Device
5 Magnetic Media
6 Others

Maintenance Equipment

Maintenance equipment that is given a type designation is set up as AN/xxM, where the first two letters after the slash (signifying Installation and Type of equipment) are followed by an M.

However, if a maintenance or test Unit or Group is considered a "part of" the item in question, it does not receive the M signifier.

For example:

Modified Power Requirements

A change in the power input voltage, phase, or frequency is denoted by addition of the letter(s) "X", "Y", or "Z". The first such modification would be denoted with an "X", the second with a "Y", the third with a "Z", the fourth with an "XX", etc. If simultaneous modifications are made that improve the equipment as well as affect power input, then both a modification letter (A, B, C, D, etc.) as well as a power requirement modification letter (X, Y, Z, etc) will be used.

For example:


A pair of parentheses surrounding where the type designation number would be located is used to signify an experimental or developmental model. Type designation number is not required but is useful for clarity. When the developmental model is ready for production, the parentheses are struck off.

For example:

Servo Amplifiers

Electronic type (non-rotating) servo amplifiers are designated "AM"; rotating type servo amplifiers are designated "PU".

Plug-in Units

Plug-in Units which can be described by their function (like receiver, microphone, loudspeaker, etc.) will use those corresponding Unit indicators. If no indicator exists to describe the plug-in's function, then the generic plug-in unit indicator (PL) will be used.

For example:

Varying Lengths

Type designators for groups and units like cables, waveguides, cords, etc. may also include a parenthetical "( -FT, -IN)" to designate the specified length. These type designators will not include a specified System/Subsystem/Center/Central/Set type designator after the / but will be given a more generic indicator like /U or /GR. However, a group or unit type designation that is already linked to a specific system/subsystem/center/central/set may use ( -FT, -IN) if the system/subsystem/center/central/set uses multiple of the group/unit and they are only distinguishable by length. This use is only for new assignments and will not be retroactive

For example:


Primary batteries (non-rechargeable) are designated using "BA"; Secondary type batteries (rechargeable) are designated using "BB".



"Part of" vs "Used with"


JETDS was adopted 16 February 1943 by the Joint Communications Board for all new Army and Navy airborne, radio, and radar equipment. Over time it was extended to cover the Marine Corps and the Navy's ship, submarine, amphibious, and ground electronic equipment. When the Air Force was established as a separate department, it continued the use of the system for electronic equipment. JETDS was adopted by the United States Coast Guard in 1950, Canada in 1951 and the NSA in 1959 (though the NSA continued to use its own TSEC telecommunications security nomenclature[2]). In 1957 the U.S. Department of Defense approved a military standard for the nomenclature, MIL-STD-196. The system has been modified over time, with some types (e.g. carrier pigeon -B-) dropped and others (e.g. computers and cryptographic equipment) added. The latest version, MIL-STD-196G, was issued in 2018.[1]

MIL-STD-196 Rev. History
Revision Date
Original 9 May 1957
A 16 September 1960
B 7 April 1965
C 22 April 1971
D 19 January 1985
E 17 February 1998
F 11 September 2013
G 30 May 2018

Derived systems

See also


  1. ^ a b c d e f g "DEPARTMENT OF DEFENSE STANDARD PRACTICE JOINT ELECTRONICS TYPE DESIGNATION AUTOMATED SYSTEM MIL-STD-196G 30 May 2018" (PDF). US DoD. Archived from the original (PDF) on 5 April 2022. Retrieved 4 April 2022.
  2. ^ Telecommunications Security (TSEC) Nomenclature System
  3. ^ Lake, Jon. "Mitsubishi F-1: Ship-killing Samurai". World Air Power Journal, Volume 23, Winter 1995. London:Aerospace Publishing. ISBN 978-1-874023-64-7. ISSN 0959-7050. p. 85
  4. ^ O'Halloran, James C. "Tien Kung I low-to-medium-altitude surface-to-air-missile system, pages 299-300," Jane's Land-Based Air Defense, 2002-2003 Edition.