(Lifted mostly from "Reference Data for Radio Engineers")
The "AN" system (now called the Joint Electronics Type Designation System or JETDS), consists of a name, followed by a type number.
A type designation assignment for equipment such as a definitive system, subsystem, center, central, set, etc., shall consist of at least an AN, a forward slash, a three-letter equipment designation, a dash, and a number. The three-letter designation is taken from Table 1.
| 1st Letter | 2nd Letter | 3rd Letter | |||
|---|---|---|---|---|---|
| (Type of Installation) | (Type of Equipment) | (Purpose) | |||
| A | Piloted Aircraft | A | Invisible light, heat radiation | A | Auxiliary assemblies (not complete operating sets used with or part of two or more sets or sets series) (INACTIVE) |
| B | Underwater mobile, submarine | B | Pigeon | B | Bombing |
| C | Air transportable | C | Carrier | C | Communications (receiving and transmitting) |
| D | Pilotless carrier | D | Radiac | D | Direction finger, reconnaissance, and/or surveillance |
| - | - | E | Nupac | E | Ejection and/or release |
| F | Fixed Ground | F | Photographic | - | |
| G | General ground use (includes two or more ground-type installations) | G | Telegraph or Teletype | G | Fire control or searchlight directing |
| - | - | - | - | H | Recording and/or reproducing (graphic meteorological and sound) |
| - | - | I | Interphone and public address | - | - |
| - | - | J | Electromechanical or inertial wire covered | - | - |
| K | Amphibious | K | Telemetering | K | Computing |
| - | - | L | Countermeasures | L | Searchlight control |
| M | Ground, mobile (installed as operating unit in a vehicle which has no function other than transporting the equipment | M | Meteorological | M | Maintenance and/or test assemblies (including tools) |
| - | - | N | Sound in air | N | Navigational aids (including altimeter, beacons, compasses, racons, depth sounding, approach, and landing) |
| P | Pack or portable (animal or man) | P | Radar | P | Reproducing |
| - | - | Q | Sonar and underwater sound | Q | Special, or combination of purposes |
| - | - | R | Radio | R | Receiving, passive detecting |
| S | Water surface craft | S | Special types, magnetic, etc., or combination of types | S | Detecting and/or range and bearing, search |
| T | Ground, transportable | T | Telephone (wire) | T | Transmitting |
| U | General utility (includes two or more general installation classes, airborne, shipboard, and ground | - | - | - | - |
| V | Ground, vehicular (installed in vehicle designed for functions other than carrying electronic equipment, etc., such as tanks | V | Visual and visible light | - | - |
| W | Water surface and underwater combination | W | Armament (peculiar to armament, not otherwise covered) | W | Automatic flight or remote control |
| - | - | X | Facsimile or television | X | Identification and recognition |
| - | - | Y | Data processing | Y | Surveillance (search, detect, and multiple target tracking) and control (both fire control and air control) |
| Z | Piloted and pilotless airborne vehicle combination | - | - | - | - |
Example: AN/VRC-12 is a radio communication set installed in a vehicle designed for functions other than carrying electornic equipment.
Or, by way of further example (from Nick England), an AN/WBW-1 would be a remote-controlled, underwater pigeon.
All groups, including commercial off-the-shelf equipment, are identified by a two-letter indicator from Table 2.
| Indicator | Family Name |
|---|---|
| OA | Miscellaneous groups |
| OB | Multiplexer and/or demultiplexer groups |
| OD | Indicator groups |
| OE | Antenna groups |
| OF | Adapter groups |
| OG | Amplifier groups |
| OH | Simulator groups |
| OJ | Consoles and console groups |
| OK | Control groups |
| OL | Data analysis and data processing groups |
| OM | Modulator and/or demodulator groups |
| ON | Interconnecting groups |
| OP | Power supply groups |
| OQ | Test set groups |
| OR | Receiver groups |
| OT | Transmitter groups |
| OU | Converter groups |
| OV | Generator groups |
| OW | Terminal groups |
| OX | Coder, decoder, interrogator, transponder groups |
| OY | Radar set groups |
| OZ | Radio set groups |
Applicable equipment indicator letters (Table 1) follow the forward slash to indicate the potential of the group for multiple or peculiar application. Example: OE-162/ARC indicates an antenna for aircraft radio-communication equipment. Equipment indicators with a specific model number (e.g., OK-450/TRC-26) are used following the forward slash when the group is peculiar to specific equipment (e.g., AN/TRC-26) with no known potential for other use.
Unit indicators are listed in Table 3.
| Indicator | Family Name | Indicator | Family Name |
|---|---|---|---|
| AB | Supports, antenna | OC | Oceanographic devices |
| AM | Amplifiers | OS | Oscilloscopes, test |
| AS | Antennas, complex and simple | PD | Prime drivers |
| AT | Antennas, simple | PF | Fittings, pole |
| BA | Batteries, primary type | PG | Pigeon articles |
| BB | Batteries, secondary type | PH | Photographic articles |
| BZ | Alarm units | PL | Plug-in units |
| C | Controls | PP | Power supplies |
| CA | Commutator assemblies, sonar | PT | Mapping and plotting units |
| CB | Capacitor banks | PU | Power equipments |
| CG | Cable assemblies, RF | R | Receivers |
| CK | Crystal kits | RC | Reels |
| CM | Comparators | RD | Recorder-reproducers |
| CN | Compensators | RE | Relay assemblies |
| CP | Computers | RF | RF components |
| CR | Crystals | RG | Cables, RF bulk |
| CU | Couplers | RL | Reeling machines |
| CV | Converters | RO | Recorders |
| CW | Radomes | RP | Reproducers |
| CX | Cable assemblies, non-RF | RR | Reflectors |
| CY | Cases and cabinets | RT | Receivers and transmitters |
| D | Dispensers | S | Shelters |
| DA | Loads, dummy | SA | Switching units |
| DT | Detecting heads | SB | Switchboards |
| DY | Dynamotors | SG | Generators, signal |
| E | Hoists | SM | Simulators |
| F | Filter units | SN | Synchronizers |
| FN | Furnitures | ST | Straps |
| FR | Frequency-measuring devices | SU | Optical devices |
| G | Generators, power | T | Transmitters |
| GO | Goniometers | TA | Telephone apparatus |
| GP | Ground rods | TB | Towed bodies |
| H | Head, hand, and chest sets | TC | Towed cables |
| HC | Crystal holders | TD | Timing devices |
| HD | Environmental apparatus (heating, cooling, etc. | TF | Transformers |
| ID | Indicators, non-cathode-ray tube | TG | Positioning devices |
| IL | Insulators | TH | Telegraph apparatus |
| IM | Intensity-measuring devices | TK | Tool kits |
| IP | Indicators, cathode-ray tubes | TL | Tools |
| J | Interface units | TN | Tuning units |
| KY | Keying devices | TR | Transducers |
| LC | Tools, line-construction | TS | Test units |
| LS | Loudspeakers | TT | Teletypewriters and facsimile apparatus |
| M | Microphones | TV | Testers, tube |
| MA | Magazines | TW | Tape units |
| MD | Modulators, demodulators, discriminators | U | Connectors, audio and power |
| ME | Meters | UG | Connectors, RF |
| MF | Magnets or magnetic-field generators | V | Vehicles |
| MK | Miscellaneous kits | VS | Signaling equipment, visual |
| ML | Meteorological devices | WD | Cables, two-conductor |
| MT | Mountings | WF | Cables, four-conductor |
| MU | Memory units | WM | Cables, multiple-conductor |
| MX | Miscellaneous | WS | Cables, single-conductor |
| 0 | Oscillators | WT | Cables, three-conductor |
| - | - | ZM | Impedance-measuring devices |
The type designation for units having one end use consists of an indicator from Table 3, a dash, a number, a forward slash, and the equipment the unit is part of or used with. Example: the receiver portion of the AN/VRC-12 is identified as R-40/VRC-12. If the unit has multiple usage, only those indicators that are common or appropriate are included after the forward slash. Examples: A power supply, part of, or used with, the AN/VRC-12 and AN/VRC-19 would be identified as PP-50/VRC. A power supply, "part of" the AN/VRC-12 and "used with" the AN/VRR-40 would be identified as PP-60/VR.
The system indicator AN does not mean that the Army, Navy and Air Force use the equipment, but simply that the type number was assigned in the AN (JETDS) system.
The reader is referred to "Miscellaneous Data" in Reference Data for Radio Engineers for further details on the AN (JETDS) nomenclature convention.