Designations Of U.S. Military Electronic And Communications Equipment

Copyright © 2000-2023 Andreas Parsch

1 Introduction

2 Early Communications Designation Systems

3 Joint Electronics Type Designation System (The "AN" System)

4 Other Designations

5 "AN" Designation Listings

6 Sources

1 Introduction

Soon after radio came in use at the beginning of the 20th century, Army and Navy started to use this new means of communication. Both services also assigned formalized designations to its radio and communications equipment almost from the beginning. These systems, however, proved cumbersome and difficult to adapt to new requirements. The expansion of World War II, and the introduction of new types of equipment (e.g. radar) finally lead to the joint "AN" designation system for all types of electronic and communications equipment. This article will describe the various designation systems in some detail.

2 Early Communications Designation Systems

The material in this section is exclusively from source [4].

2.1 Army

The Army used a numbering system for its radio communications equipment since at least World War I. The system distinguished between complete sets and components.

Sets:
Sets were designated with a type designator and a sequential model number, separated by a dash. Each designator used its own sequential number series, starting with 1. The following types were defined:

• SCM - Set, Complete, Meteorological
• SCR - Set, Complete, Radio (often interpreted as "Signal Corps Radio")
• SCS - Set, Complete, System (groups of several SCR sets)

Sometimes, modifications were indicated using additional letters, as in SCR-211-C or SCR-AH-183.

Components and Equipment:
Components and associated items were also designated using a type designator and a model number, separated by a dash. Type designators for radio communications components and equipment were:

• A - Phantom Antenna
• AL - Aerial Communication
• AN - Antenna Aerial
• AP - Panel Set
• AR - Lightning Arrestor
• BA - Primary Battery
• BC - Basic Component (receiver, transmitter, control box, etc.)
• BD - Switchboard, Power Board, etc.
• BE - Cabinet, Starting Box, etc.
• BG - Bag, Case, Fabric, Cover, etc.
• BK - Circuit Breaker, Relay
• BX - Box
• BZ - Buzzer
• C - Induction Coil, etc.
• CA - Capacitor
• CC - Electrical Connecting Cord
• CD - Electrical Cord with Plug
• CE - Animal Pack Equipment
• CF - Telephone (carrier)
• CH - Chest
• CO - Electrical Extension Cord
• CP - Cable (counterpoise)
• CS - Carry Case
• DC - Crystal or Crystal Unit
• DM - Dynamotor
• DR - Wire Reel
• EE - Telephone, Telegraph or Signal Lamp Set
• F - Fairlead
• FL - Filter
• FM - Supporting Frame
• FT - Fitting, Mounting, Clamp, etc.
• GA - Spark Gap
• GC - Hand Crank
• GE - Gasoline Engine
• GN - Generator
• GP - Ground Rod
• GR - Sound and Flash Ranging Set
• GY - Guy or Stake
• HO - Shelter
• HS - Headset
• I - Ammeter, Voltmeter, Clock, etc.
• IE - Instrument Equipment
• IN - Insulator
• IS - Electrical Instrument
• J - Transmitting Key
• JB - Jack Box
• JK - Jack, Receptacle
• K - Cart, Truck, Trailer, etc.
• KE - SCS Equipment (Vehicular)
• LC - Telephone Line Construction Tool or Apparatus
• LG - Leg
• LM - Illuminating Lamp or Bulb
• LP - Loop
• LS - Loudspeaker
• M - Miscellaneous
• MA - Radio Mast, less Antenna
• MC - Miscellaneous Component
• ME - Maintenance Equipment
• MG - Motor Generator
• ML - Meteorological Apparatus
• MO - Motor
• MP - Mast Base, Bracket, Clamp
• MS - Mast Section
• P - Headset
• PA - Public Address Equipment
• PE - Power Unit
• PH - Photographic Article
• PL - Plug
• PN - Mounting Panel
• R - Telephone Receiver
• RA - Rectifier
• RL - Reel Mechanism
• RM - Remote Control Unit
• RS - Resistor
• RU - Water Cooler
• SE - Signal Set
• SG - Shafts or Gear
• SO - Socket, etc. (Connector)
• ST - Carrying Strap, etc.
• SW - Switch
• T - Telephone Transmitter or Microphone
• TC - Central Office Set (wire)
• TD - Chest Set
• TE - Tool Equipment
• TF - Power Transformer
• TG - Telegraph Instrument
• TL - Tool
• TM - Terminal, Connector, etc.
• TP - Telephone (desk set, etc.)
• TR - Tower
• TS - Handset (wire)
• TU - Transmitter Tuning Unit
• VB - Vibrator
• VO - Oscillator
• VT - Vacuum Tube
• W - Wire
• WC - Cable

2.2 Navy

Beginning around 1910, the Navy assigned alphanumerical type designations codes to its radio communication equipment.

Sets and Systems:
Two letters were used, where the first letter indicated the type of equipment, while the second letter served as a sequential model letter, e.g. "RB" was the second receiver. When the single letter model sequence was exhausted, this was extended to three letters, e.g. "RZ" was followed by "RAA", "RAB", etc.
Some type letters used "sub-series", in which the second letter of the 3-letter designator was not assigned sequentially, but indicated the sub-type of the equipment. Examples (like type letter "A") can be found in the type letter listing below.
Later versions of a system would receive a numerical suffix, i.e. "RAK-1" for the second version of "RAK", "RAK-2" for the third, etc. Modifications after delivery resulted in lower case suffixes, like "RAK-1a", "RAK-1b", etc. Prototypes and test models of an equipment item were designated with an "X-" prefix, e.g. the prototype for the "RAK" would be an "X-RAK".
The following type letters were defined:
(listing copied verbatim from source [4])

Model     Type of Equipment
 
A-- ---   Airborne Radio and Radar Equipment
    AB-   Airborne IFF
    AI-   Airborne Radar Intercept
    AM-   Airborne Radio Transmitting and Receiving
    AR-   Airborne Radio Receiving
    AS-   Airborne Search Radars
    AT-   Airborne Radio Transmitting
    AY-   Airborne Radar Altimeters
B-- ---   Ship-Shore IFF Equipment
C-- CX    All Commercial Experimental Equipment
D-- ---   Ship-Shore Radio and Radar Direction Finding Equipment
    DX-   Assembled Direction Finder Equipments (DF assemblies 
          which when used with a standard receiver form a 
          complete DF equipment.)
E-- ---   Emergency Power Equipment (Gasoline or Diesel engine 
          generator sets)
F-- ---   Radar Fire Control Equipment ("F" series superseded by 
          the BuOrd Radar Mark/Mod series)
    ---   Subseries of "F" series in use for other than fire 
          control radar, as follows:
    FP-   Facsimile Recording Equipment.
    FQ-   Facsimile Scanning Equipment.
    FR-   Frequency Shift Receiver Converter Equipment.
    FS-   Frequency Shift Keying Equipment.
G-- ---   Airborne Radio Transmitting Equipment (Classification 
          cancelled - Reassigned "AT" series.)
H-- ---   Hoist Train Mechanism (Cancelled - hoist train 
          mechanism considered as part of an equipment.)
I-- ---   Intercept Radar.
J-- ---   Sonar-Sound Listening (Receiving).
L-- ---   Precision Calibrating Equipment.
M-- ---   Radio Transmitting and Receiving Equipment.
N-- ---   Sonar Echo Sounding.
    NA-   Sonar Beacon.
    NG-   Echo Sounding (Rochelle Salt).
    NJ-   Lightweight Echo Sounding Recording.
    NK-   Portable Echo Sounding Recording.
    NM-   Echo Sounding (Magnetostriction).
O-- ---   Measuring, Test, and Operator Trainer Equipments for 
          Models OA to OCZ inclusive.  For Models after OCZ, the 
          subseries breakdown is as follows:
    OE-   Xmtr and/or Rcvr Analyzers, Vacuum-Tube Voltmeters, 
          Volt-Ohm-Milliammeters, Multimeters.
    OF-   Echo Boxes, Wavemeters, Frequency Meters (non-
          precision).
    OG-   Signal Generators (non-precision), Test Oscillators
    OK-   Sonar Computers.
    OM-   Test Monitor Equipment.
    OP-   Signal and Sound Wave Measuring Equipment, Noise 
          Meters.
    OS-   Oscilloscopes.
    OT-   Radar Operator Trainers.
    OV-   Vacuum Tube Analyzers or Testers.
    OW-   Sonar Test Equipment.
    OZ-   Impedance Measuring Equipment.
P-- ---   Automatic Transmitting and Receiving Equipment Coding 
          Equipment.
Q-- ---   Sonar Echo-Ranging-Listening Equipments:
    QA-   E/R/L (Quartz).
    QB-   E/R/L (Rochelle Salt).
    QC-   E/R (Magnetostriction) with L (Rochelle Salt).
    QD-   Depth Determining Equipment.
    QF-   Teacher and Training Equipment.
    QG-   Console Version of "QC" Series.
    QJ-   Console Version of "QB" Series.
    QK-   Scanning Sonar-Crystal.
    QL-   Frequency Modulated Sonar.
    QX-   Auxiliary Equipments to Echo Ranging Sonar.
R-- ---   Radio Receiving Equipment (Panoramic radio adapters 
          were included in this class up through Model REZ).
    RP-   Panoramic Radio Adapters.
S-- ---   Search Radar Equipment.
T-- ---   Radio Transmitting Equipment.
    TP-   Power Amplifiers.
U-- ---   Remote Control:
    UX-   Mobile Remote Control.
V-- ---   Visual - PPI Repeaters.
W-- ---   Sonar - Combined Ranging and Sounding:
    WA-   Combined Sounding-Ranging (Magnetostriction).
    WB-   Combined Sounding-Ranging (Rochelle Salt).
    WC-   Combined Sounding-Ranging (R/S Sounding) (M/S & R/S 
          Ranging & Listening).
    WD-   Combined Sounding-Ranging (R/S Sounding) (M/S & R/S 
          Ranging & Listening)
    WE-   Combined Lightweight M/S Echo Ranging with sounding 
          feature removed.
    WF-   Combined Ranging-Sounding-Listening (Sonic & supersonic 
          listening using ADP crystals).
X-- ---   Experimental (Navy-designed).
Y-- ---   Navigation and Landing Equipment: (other than direction 
          finders), (beacons).
Z-- ---   Airborne Navigation and Landing. (Classification 
          cancelled - reassigned "AY" series).

Components:
Components and parts of a system received separate designations, as follows:

(1) was a letter code for the manufacturer, the first letter always being a "C". Initially, only two letters were used, but this was later extended to 3 and 4 letters.

The two-digit code (2) indicated the class or type of the component. The following table lists the type codes:
(listing copied verbatim from source [4])

Class   Material
 
10      Miscellaneous: To be used when a definite class is not 
        available.
14      Special RF Devices (Not covered by any other 
        classification).  (Electronic switching, etc.)
18      Prime Movers and Accessories: All types except 
        electrical.
19      Batteries:  All types; parts and accessories.
20      Rectifier Power Units - Voltage Regulators - Copper Oxide 
        Rectifiers: All types.  A20 is crystal detectors.
21      Motors - Generators - Dynamotors - Motor Generators - 
        Rotary Converters, etc.  Motor controllers.
22      Instruments - Electrical Indicating and Recording.
23      Control Panels and Control Units. (Except motor 
        controllers.)
24      Switches: Manually operated.
25      Shields and Shielding Material: Finishes.
26      Keys - Telegraph: Manually operated.
28      Protective Devices: Static types.
29      Electromagnetic Contact Devices: All types.
30      Transformers and Reactors: Power and audio.
35      Oscillators - Complete Units (Audio or RF).
36      Ranging Equipment - Radio (Localizer, rotating beacons, 
        etc.)
38      Vacuum Tubes - Photo-electric Cells: All types.
40      Piezo-Electric Crystals and Holders - Thermometers and 
        Thermostats.
41      Compensators - Underwater Sound.
43      Transmitter-Receiver Units (Combined): Equipment in which 
        the transmitter and receiver are not separable as units.
46      Receiver Units and Converters (RF to IF, etc.) - Radio 
        and Sound.
47      RF Transformers - Inductors - Chokes.
48      Capacitors: All types.
49      Head Telephones - Telephone Cords - Patch Cords - 
        Loudspeakers - Plugs - Jacks - Sockets - Receptacles: All 
        types.
50      Amplifier, Modulator, and Coupler Units - Electronic 
        Converters - Mixing Panels: All types. (Complete diplex 
        and duplex units.) See 14 for electronic switching.
51      Microphones - Hydrophones - Underwater Sound Electrical 
        Pickup Devices - Combination Handsets: All types.
52      Radio Transmitter Units: Includes RF drivers for 
        underwater sound equipment, etc.
53      Filter Units: All electrical types.
54      Sound Receiving Devices - Acoustical.
55      Indicators and Recorders: Radio, radar, and underwater 
        sound.  (Indicating instruments under Class 22.)
56      Wave Propagation.
59      Television - Photo - Radio.
60      Test Equipment (Integral instruments under Class 22.) A60 
        is Training Equipment (Operator trainers and instruction 
        devices.)
61      Insulators and Insulating Material: Phenolic and ceramic.
62      Wires and Conductors - Junction Boxes.  A62 is RF 
        transmission lines and RF cables, etc.
63      Resistors:  All types.
64      Static Recorders and Eliminators.
65      Remote Control Systems by Wire: Repeater systems, etc.
66      Antennas - Antenna Assemblies.  (Dummy and phantom 
        antennas.)
67      Automatic Systems, Facsimile, Tele-Automatic: Automatic 
        keyers and recorders.
68      Secrecy Systems: Sending and receiving. (Speech 
        scrambling)
69      Direction Finding Equipment: Radio.
70      Distance Finding: A70 is radio altimeters.
72      Portable Equipment - Field Sets.
73      Combined Gas Engine Generator Sets.
74      Precision Calibration and Measuring Equipment.
75      Standards: (Including standardization notices, etc.)
78      HF Underwater Sound Projector (above 10 Kc) and 
        supporting parts.
79      LF Underwater Sound Projector (10 Kc or below).
83      Frequency Control Systems.
84      Control by Radio.
85      Interference Reduction.
87      Experimental Superfrequency Equipment.
88      Instrument Landing Equipments.
89      Radio Recognition and Identification Devices.
90      Visual Signalling Apparatus (This classification for type 
        number assignments only).

(3) was the number of the specific model, consisting of 2, 3 or 4 digits, resulting in a 4-, 5- or 6-digit model designation. Secret equipment used 3-letter codes instead of model numbers.

(4) was an optional suffix to designate modifications. Normal designations had upper case letter suffixes, while designations for secret equipment had numerical suffixes.

3 Joint Electronics Type Designation System (The "AN" System)

3.1 History

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-196G, released on 30 May 2018. The most significant change in recent years was the creation of a completely computer-based system for allocation and management of designations. The system is now officially known as JETDAS - Joint Electronics Type Designation Automated System.

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", and a brief explanation of all terms relevant to the discussion of JETDS can be found here. JETDS does not designate parts and assemblies, and uses different designation schemes for the other item types.

3.2 Sets And Systems

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

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.

Notes:

3.3 Components (Groups And Units)

Groups and units (i.e. the components of complete sets and systems) are designated as follows:

The one- or two-letter code (1) indicates the type of the unit or group.

Group indicators:

• OA - Miscellaneous Group (only used, if no other indicator applies)
• OB - Multiplexer and/or Demultiplexer Group
• OD - Indicator Group
• OE - Antenna Group
• OF - Adapter Group
• OG - Amplifier Group
• OH - Simulator Group
• OI - Cryptographic Group
• OJ - Consoles and Console Group
• OK - Control Group
• OL - Data Analysis and Data Processing Group
• OM - Modulator and/or Demodulator Group
• ON - Interconnecting Group
• OP - Power-Supply Group (non-rotating types)
• OQ - Test Set Group
• OR - Receiver Group
• OS - Satellite Group (see note 1)
• OT - Transmitter Group
• OU - Converter Group
• OV - Generator Group
• OW - Terminal Group
• OX - Coder, Recoder, Interrogator, Transponder Group
• OY - Radar Set Group
• OZ - Radio Set Group (not used, if OE, OR or OT can be applied)

Unit indicators:

• AB - Support for Antenna ("antenna base")
• AM - Amplifier
• AS - Antenna, Simple and Complex
• (AT - Antenna, Simple; this unit designator has been removed from the system; now covered by AS)
• BA - Battery, Primary Type (non-rechargeable)
• BB - Battery, Secondary Type (rechargeable)
• BZ - Alarm Unit ("buzzer")
• C - Control
• CA - Computer Auxiliary Unit (like peripheral devices, etc.)
• (CA - Commutator Assembly; this unit designator has been removed from the system)
• (CB - Capacitor Bank; this unit designator has been removed from the system)
• CC - Cable Assembly, RF
• CD - Controlling Device
• (CG - RF Cable & Transmission Line; this unit designator has been removed from the system; now covered by CC)
• (CK - Crystal Kit; this unit designator has been removed from the system)
• CM - Comparator
• CN - Compensator
• CP - Computer
• (CR - Crystal; this unit designator has been removed from the system)
• CU - Coupler
• CV - Converter (Electronic)
• CW - Radome
• CX - Cable Assembly, non-RF
• CY - Case or Cabinet
• D - Dispenser
• DA - Dummy Load (electrical test loads)
• DI - Data Transmission Device
• DT - Detecting Head
• DU - Display Unit/Monitor (peripheral device for computers etc.) (see note 2)
• (DY - Dynamotor; this unit designator has been removed from the system)
• (E - Hoist; this unit designator has been removed from the system)
• F - Filter Unit
• (FN - Furniture; this unit designator has been removed from the system)
• FO - Fiber Optics Device
• FR - Frequency Measuring Device
• G - Power Generator (see also PU)
• GO - Goniometer
• (GP - Ground Rod; this unit designator has been removed from the system)
• H - Head, Hand or Chest Set
• (HC - Crystal Holder; this unit designator has been removed from the system)
• HD - Environmental Apparatus
• ID - Indicator Unit (non-cathode ray tube)
• (IL - Insulator; this unit designator has been removed from the system)
• IM - Intensity Measuring Device
• IP - Indicator Unit (cathode ray tube)
• J - Interface Unit ("Junction")
• KG - Key Generator
• KY - Keying Device
• LA - Laser
• (LC - Line Construction Tool; this unit designator has been removed from the system)
• (LM - Lamp; this unit designator has been removed from the system)
• LS - Loudspeaker
• M - Microphone
• (MA - Magazine; this unit designator has been removed from the system)
• MD - Modulator, Demodulator or Discriminator
• ME - Meter
• (MF - Magnetics or Magnetic Field Generators; this unit designator has been removed from the system)
• MK - Miscellaneous Kit
• ML - Meteorological Device
• MO - Multipurpose Unit
• MT - Mounting
• MU - Memory Unit
• MW - Microwave Device
• MX - Miscellaneous
• O - Oscillator
• OC- Oceanographic Device
• OS - Oscilloscope, Test (see note 1)
• (PD - Prime Driver; this unit designator has been removed from the system)
• (PF - Pole Fitting; this unit designator has been removed from the system)
• (PG - Pigeon Article; this unit designator has been removed from the system)
• (PH - Photographic Article; this unit designator has been removed from the system)
• PL - Plug-In Unit
• PP - Power Supply (non-rotating types)
• PT - Mapping or Plotting Unit
• PU - Power Equipment (rotating)
• R - Receiver
• RB - Robotics
• (RC - Reel; this unit designator has been removed from the system)
• RD - Recorder/Reproducer
• RE - Relay Assembly Unit
• (RF - Radio Frequency Unit; this unit designator has been removed from the system)
• (RG - Bulk RF Cable; this unit designator has been removed from the system)
• RL - Reeling Machine
• RO - Recorder
• RP - Reproducer
• (RP - Rope and Twine; this unit designator has been removed from the system)
• RR - Reflector
• RT - Receiver/Transmitter
• S - Shelter
• SA - Switching Unit
• SB - Switchboard
• SG - Signal Generator
• SM - Simulator
• SN - Synchronizer
• SS - Special Purpose Device
• (ST - Strap; this unit designator has been removed from the system)
• SU - Electro-Optical Unit
• SY - Secure Speech Device
• T - Transmitter
• TA - Telephone Apparatus
• TB - Towed Body
• (TC - Towed Cable; this unit designator has been removed from the system)
• TD - Timing Device
• TF - Transformer
• TG - Positioning Device
• TH - Telegraph Apparatus
• (TK - Tool Kit; this unit designator has been removed from the system)
• (TL - Tool; this unit designator has been removed from the system)
• TN - Tuning Unit
• TR - Transducer
• TS - Test Unit
• TT - Teletypewriter or Facsimile Apparatus
• TU - Television
• (TV - Tube Tester; this unit designator has been removed from the system)
• TW - Tape Unit
• (U - Audio and Power Connector; this unit designator has been removed from the system)
• (UG - RF Connector; this unit designator has been removed from the system)
• V - Vehicle
• (VS - Visual Signalling Equipment; this unit designator has been removed from the system)
• (WD - Cable, 2 Conductors; this unit designator has been removed from the system)
• (WF - Cable, 4 Conductors; this unit designator has been removed from the system)
• (WM - Cable, Multiple Conductors; this unit designator has been removed from the system)
• (WS - Cable, Single Conductor; this unit designator has been removed from the system)
• (WT - Cable, 3 Conductors; this unit designator has been removed from the system)
• ZM - Impedance Measuring Device

(2) is the model number. Each unit or group indicator uses its own model number sequence, starting at 1. Blocks of high model numbers are reserved for use by Canada (5000-5999, 25000-25999), Australia (20000-20999), New Zealand (21000-21999) and the UK (22000-22999).

The optional suffix letter (3) 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.

(4) The full type designation of a group or unit includes a slant bar, followed by the designation of the set or system, of which it is a part. If the equipment can be used with several systems, a more general designator is appended. E.g. the MD-945/TSC is a modulator, which is used with several AN/TSC-n systems, while the AS-22/AP is an antenna, which is used with several airborne radar sets/systems with different purpose indicators. A designation for a general purpose component, i.e. one that is not designed to be used in a specific environment, should use only the general installation letter "U" after the slant bar. However, the "/U" suffix is often omitted in these cases.

(5) The "(V)" symbol indicates an equipment (usually a group) with variable components. A number following the "(V)" is used to designate a specific version of the equipment, i.e. with a specific component configuration.

Notes:

3.4 Miscellanea

3.4.1 Training Equipment

Training items designed to be used with a certain equipment item are designated by adding "-Tn" to the equipment designator. E.g., the second training set for the AN/APQ-13 radar set is designated as AN/APQ-13-T2. If a set/system can be used for training with several sets/systems of a certain type, the model number is omitted. E.g., AN/APG-T1 is the first training set designed to be used with several AN/APG-n systems. If a set/system can be used for training with equipment in different installation locations, installation letter "U" is used, e.g. AN/URC-T1 is a training set for both airborne (AN/ARC-n) and ground (AN/GRC-n) radio communicators.

3.4.2 Power Input Modifications

Modifications of an equipment, which only change the electrical power input requirements (e.g. different voltage and/or frequency), are not indicated by the "standard" modification letters "A", "B", etc., but by the three reserved letters "X", "Y" and "Z". These can also be combined, e.g. AN/ARC-51BX is the first power input modification of the AN/ARC-51B. If more than 3 power input modifications exist for a specific equipment, multiple suffix letters ("XX", "YY", etc.) are used.

3.4.3 Development Indicator

During the development phase of an equipment item, a development indicator like (XN-1) may be appended to the basic equipment designation. The letter combination always starts with "X" and indicates the organization responsible for the development, and the number is a sequential series number (using separate series for each combination of equipment designator and developing organization). E.g., the AN/APS-73(XH-3) is the third developmental model of the basic AN/APS-73 by the Air Force Aerial Reconnaissance Laboratory.
The following letter combinations for organizations have been defined over the years (not all of them are still used today):

• XA - Air Force: Aeronautical Systems Division, Wright Patterson AFB OH
• XB - Navy: Naval Research Laboratory, Washington DC
• XC - Army: Communications-Electronics Command (CECOM), Fort Monmouth NJ
• XD - Air Force: Electronics Systems Division, Hanscom AFB MA
• (XE - Army: Electronics Laboratory, Fort Monmouth NJ; no longer used)
• (XF - Army: Frankfort Arsenal, Philadelphia PA; no longer used)
• XG - Navy: Naval Ocean Systems Center, San Diego CA
• (XH - Air Force: Aerial Reconnaissance Laboratory, Wright-Patterson AFB OH; no longer used for new assignments)
• XI - Air Force: Munitions Systems Division, Eglin AFB FL
• XJ - Navy: Naval Air Development Center, Warminster PA
• (XK - Air Force: Flight Control Laboratory, Wright-Patterson AFB OH; no longer used for new assignments)
• (XL - Army: Signal Electronics Research Unit, Mountain View CA; no longer used)
• (XM - Army: Signal Engineering Laboratories, Hexagon, Fort Monmouth NJ; no longer used)
• XN - Navy: Department of the Navy, Washington DC
• XO - Army: Missile Command (MICOM), Redstone Arsenal AL
• XP - Canadian Department of Defense, Ottawa
• (XQ - Air Force: Aeronautical Accessories Laboratory, Wright-Patterson AFB OH; no longer used for new assignments)
• XR - National Security Agency, Fort Meade MD
• (XR - Army: Engineering Research & Development Command; no longer used)
• (XS - Air Force: Electronic Components Laboratory, Wright-Patterson AFB OH; no longer used for new assignments)
• XT - Army: Intelligence & Security Command (INSCOM), Arlington Hall Station VA
• XU - Navy: Naval Underwater Systems Center, New London CT
• XV - Air Force: Air Force Weapons Laboratory, Kirtland AFB NM
• XW - Air Force: Rome Air Development Center, Griffiss AFB NY
• (XY - Air Force: Weapons Guidance Laboratory, Wright-Patterson AFB OH; no longer used for new assignments)
• (XZ - Navy: Bureau of Naval Weapons Activities; no longer used)
• (XAA - Air Force: Space & Missile Systems Organization, Norton AFB CA; no longer used)
• (XAE - Army: Research & Development Activity, Fort Huachuca AZ; no longer used)
• XAN - Navy: Naval Avionics Center, Indianapolis IN
• XAV - Army: Aviation Research & Development Command (AVRADA), Fort Monmouth NJ
• (XBB - Army: Electronics Command, Proc & Prd Division, Fort Huachuca AZ; no longer used)
• XBS - Air Force: Ballistic Systems Division, Norton AFB CA
• XCA - Navy: Naval Weapons Support Center, Crane IN
• (XCC - Air Force: Air Force Missile Test Center, Patrick AFB FL; no longer used)
• XCL - Navy: Naval Weapons Center, China Lake CA
• (XCR - Navy: Naval Weapons Center, Corona Laboratory, Corona CA; no longer used)
• (XDD - Army: Signal Air Defense Engineering Agency, Fort Meade MD; no longer used)
• XDV - Navy: Naval Surface Weapons Center. Dahlgren VA
• XER - Army: Electronics Research & Development Command (ERADCOM), Adelphi MD
• XGS - Navy: Ground Support Equipment Division, Naval Air Engineering Center, Lakehurst NJ
• XIH - Navy: Naval Ordnance Station, Indian Head MD
• (XLW - Army: Limited Warfare Laboratories, Aberdeen Proving Ground MD; no longer used)
• XME - Army: Mobility Equipment Research & Development Command (MERADCOM), Fort Belvoir VA
• XMG - Navy: Pacific Missile Test Center, Point Mugu CA
• XPC - Navy: Naval Coastal Systems Laboratory, Panama City FL
• (XPM - Army: Project Michigan, Ypsilanti MI; no longer used)
• (XSC - Army: Army Satellite Communications Agency, Fort Monmouth NJ; no longer used)
• XSS - Air Force: Space Systems Division, Los Angeles AFB CA
• XUC - Navy: Naval Undersea Center, San Diego CA
• XWH - Navy: Naval Weapons Station, Earle NJ
• XWO - Navy: Naval Surface Weapons Center, White Oak Laboratory, Silver Spring MD

3.4.4 Additional Type Indicators for Data Processing Equipment

Designators for data processing sets and systems (type indicator "Y") can optionally be further detailed to indicate the characteristics of the equipment. In this case, additional digits in parentheses are inserted behind the installation-type-purpose designator, e.g. AN/UYK(1,4,5)-n. The following digits can be used:

• 1 - Digital Equipment
• 2 - Analog Equipment
• 3 - Analog/Digital Hybrid
• 4 - Input/Output Device
• 5 - Magnetic Media
• 6 - Other

3.4.5 Additional Parenthetical Designators

There are two other designators, which are used in a way similar to the "(V)" for variable configuration equipment, i.e. they are appended behind the model number. These designators are:

• (C) - Classified and/or Cryptographic Equipment (for use by NSA only)
• (P) - Plug-In Accepting Unit (used only for units or groups which accept optional "plug-ins" to enhance functionality; (P) is never used in "AN/" designations for sets and systems)

An example, which uses both of these designators, is RT-1539A(P)(C)/G.

3.4.6 Preliminary Designators

If an equipment item has not yet received an official designation, it can be referred to using a designation, where the model number has been replaced by parentheses. E.g., a new fire control radar system could be identified as AN/APG-() in the initial development phase.

4 Other Designations

4.1 BuAer Defensive Fire Control Systems

[The information in this section was contributed by Chuck Hansen. Thanks!]

The postwar U.S. Navy Bureau of Aeronautics (BuAer) assigned "AERO" designations to many different types of equipment, that were used on postwar US Navy aircraft. More specifically, "AERO" designations were assigned to aircraft ordnance equipment and accessories, including tow targets, gunsights, bombsights, target carriers, gun chargers, turrets, bomb shackles, bomb and torpedo racks, launchers and ejectors, bomb trailers and skids, and bomb and torpedo hoists. The following table lists the AERO numbers assigned to airborne defensive fire control systems.

4.2 US Air Force QRC (Quick Reaction Capability) Programs, 1952 - 1964

[The information in this section was contributed by Per Nyström. Thanks!]

The following text is quoted from "The History of US Electronic Warfare" (source [5]), Volumes 2 and 3:

AIR FORCE QUICK REACTION CAPABILITY PROGRAMS, 1952 TO 1964

In 1952, mid-way through the Korean War, the US Air Force issued a new directive entitled "Quick Reaction Capability (QRC) for ECM". This procedure was to be used when it was necessary to procure quickly limited quantities of new equipment, to counter new enemy electronic threats as they were discovered. The program used production procurement funds, which are larger than those for research and development. The ECM Branch of the Aircraft Radiation laboratory at Wright Field was assigned technical responsibility for the resultant QRC equipments designed for airborne use, and the Air Force Supply Depot at Gentile AFB held procurement responsibility. Early in the program an in-house QRC facility was established at the Rome Air Development Center for building ground-based systems. Following a competitive bid the Hallicrafters Company at Chicago won the contract to become sole source contractor to built QRC systems, and held the position throughout most of the 1950s. As electronic warfare increased in importance the company did well out of the program. It also enjoyed an advantage over competitors, when the Air Force wanted QRC equipments placed in production. In 1959, following strong representations from competing companies, the Air Force revised the QRC program to allow any suitable company to bid for the work.

Usually a QRC program would provide engineering prototypes or a few production models of an equipment, plus sufficient spare parts for one year's operation. In a very few cases, however, as many as 100 examples of a specific equipment might be built. Later the Navy and the Army would initiate QRC programs of their own, though the other two services would use them far less than the Air Force. The Navy equipments built under QRC contracts carried regular equipment designators rather than QRC designators, making them difficult to identify. The Army ran its own system of QRC designators in parallel with that used by the Air Force, also starting from QRC-1.

The List of QRC Programs from [5] gives brief details of the first 232 Air Force QRC programs, spanning the period between the date of the initiation of the procedure and the end of 1964. A few post-1964 numbers are also listed, but the list is incomplete from this date on.

In more recent days there appears to be a continued use of "QRC" designations but in a slightly different format. There are references to projects with designations like QRC xx-yy, where xx is 83 or 84, possibly indicating a year, and yy is a low number, up to 05, possibly a consecutive series of QRC projects for that year. QRC may also be read as "Quick Reaction Contract" in these cases. A list with a few of these designations can be found here.

5 "AN" Designation Listings

Note: Special thanks go to David Huie. Without his active help, the designation listings on this site wouldn't be anywhere near as complete as they are now!

Because some of the AN equipment listings are fairly large, I provide them in separate files. If a certain AN/Axx, AN/Cxx, AN/Dxx or AN/Zxx code is not listed, then I don't know any equipment item using that designator.

The reasons, why I do not attempt to include listings of equipment with installation-letters other than "A", "C", "D" and "Z" are:
- The topic of my site are military aviation designations.
- I really do have very few data about other "AN" designations, because my library is almost completely aviation related.
The AN/USD category is listed, because it includes several drone surveillance systems, and is therefore "on-topic" for an aviation related site.

Notes for the designation lists:

• When a designation is listed without any details, this means that I have seen the designation somewhere (so the equipment exists, unless the reference was a typo), but I have not found any information about the equipment. Therefore, such entries are generally best be considered as "unconfirmed".
• When I list aircraft, which used a certain equipment item, this list is usually not complete. I list only those aircraft types, for which I have found a reference.

AN/AAx - Airborne Infrared Equipment

AN/ACx - Airborne Carrier Signal Based Equipment

AN/ADx - Airborne Radiological Equipment

AN/AEx - Airborne Laser Equipment

AN/AGx - Airborne Teletype Equipment

AN/AIx - Airborne Interphone Equipment

AN/AJx - Airborne Electromechanical Equipment

AN/AKx - Airborne Telemetering Equipment

AN/ALx - Airborne Countermeasures Equipment

AN/AMx - Airborne Meteorological Equipment

AN/ANx - Airborne Sound Equipment

AN/APx - Airborne Radar Equipment

AN/AQx - Airborne Sonar Equipment

AN/ARx - Airborne Radio Equipment

AN/ASx - Airborne Special/Combination Equipment

AN/ATx - Airborne Telephone (Wire) Equipment

AN/AVx - Airborne Visual/Light Equipment

AN/AWx - Airborne Armament Equipment

AN/AXx - Airborne Television/Telefax Equipment

AN/AYx - Airborne Data Processing Equipment

AN/Cxx - Air Transportable Equipment

AN/Dxx - Missile/Drone Equipment

AN/Uxx - General Utility (or Multiple Installation) Equipment

AN/Zxx - Airborne (Piloted/Pilotless Combination) Equipment

6 Sources

[1] Department of Defense: MIL-STD-196G "Joint Electronics Type Designation System"
[2] Department of Defense: MIL-HDBK-505 "Handbook For Definitions Of Item Levels, Item Exchangability, Models And Related Terms"
[3] Department of Defense: MIL-HDBK-1812 "Type Designation, Assignment And Method For Obtaining"
[4] Ray Mote: "World War Two Nomenclature Systems", in ELECTRIC RADIO Magazine, June & July 1995
[5] Association of Old Crows: "The History of US Electronic Warfare"

(The designation listings were compiled using a wide variety of sources, not the least of which were the Internet and contributions by fellow researchers.)