| First Letter Launch Environment | Second Letter Mission Symbols | Third Letter Vehicle Type |
| A - Air B - Multiple C - Coffin H - Silo stored L - Silo launched M - Mobile P - Soft Pad R - Ship U - Underwater | D - Decoy E - Special electronic G - Surface attack I - Intercept, aerial Q - Drone T - Training U - Underwater attack W - Weather | M - Guided Missile N - Probe (non-orbital instruments) R - Rocket (without installed or remote control guidance) |
U.S. military electronic equipment is assigned an identifying alphanumeric designation that is used to uniquely identify it. This system is commonly called the "AN" designation system, although its formal name is the Joint Electronics Type Designation System (JETDS). The letters AN preceding the equipment indicators formerly meant "Army/Navy," but now are a letter set that can only be used to indicate formally designated DOD equipment. The first three letters following the "AN/" indicate Platform Installation, Equipment Type, and Equipment Function, respectively. The appropriate meaning is selected from the lists below. The letters following the AN designation numbers provide added information about equipment. Suffixes (A, B, C, etc.) indicate a modification. The letter (V) indicates that variable configurations are available. The letter (X) indicates a development status. A parenthesis ( ) without a number within it indicates a generic system that has not yet received a formal designation, e.g., AN/ALQ( ). Quite often the () is pronounced "bow legs" since they look like the shape of cowboy legs.
| First Letter Platform Installation | Second Letter Equipment Type | Third Letter Function or Purpose |
| A - Piloted aircraft B - Underwater mobile, submarine D - Pilotless carrier F - Fixed ground G - General ground use K - Amphibious M - Mobile (ground) P - Portable S - Water T - Ground, transportable U - General utility V - Vehicular (ground) W - Water surface and underwater combination Z - Piloted-pilotless airborne vehicle combination | A - Invisible light, heat radiation C - Carrier D - Radiac F - Photographic G - Telegraph or teletype I - Interphone and public address J - Electromechanical or inertial wire covered K - Telemetering L - Countermeasures M - Meteorological N - Sound in air P - Radar Q - Sonar and underwater sound R - Radio S - Special or combinations of types T - Telephone (wire) V - Visual and visible light W - Armament X - Facsimile or television Y - Data Processing | B - Bombing C - Communications D - Direction finder, reconnaissance and/or surveillance E - Ejection and/or release G - Fire control or searchlight directing H - Recording and/or reproducing K - Computing M - Maintenance and/or test assemblies N - Navigation aids Q - Special or combination of purposes R - Receiving, passive detecting S - Detecting and/or range and bearing, search T - Transmitting W - Automatic flight or remote control X - Identification and recognition Y - Surveillance and control |