Now go to

US Army-Navy equipment designations

US Army-Navy component designations





Letter Symbols Used in Making Basic Indicators           

First Letter, Installation     Second Letter, Type of Equipment       Third Letter, Purpose
A - Airborne (installed assemblies

and operated in aircraft) operating

B - Pigeon A-Auxiliary (not complete sets)
C - Air transportable C - Carrier (wire) C - Communications
D - Pilotless carrier   D - Direction finder
F - Ground, fixed F - Photographic  
G - Ground, general use G - Telegraph or teletype (wire) G - Gun directing
  I - Interphone or public address  
K- Amphibious control K- Telemetering  
  L- Countermeasures L - Searchlight
M- Ground, mobile M- Meteorological M - Maintenance and test

assemblies, also tools

  N - Sound in air N - Navigational
P- Pack or portable P- Radar P - Reproducing, photographic or sound
  Q- Underwater sound Q - Special types
  R - Radio R - Receiving
S - Shipboard S - Special types S - Search and/or detecting
T- Ground, transportable T- telephone (wire) T - Transmitting
U - General utility    
V- Ground, vehicular V - Visual and light  
    W - Remote control
  X - Facsimile and television X - Identification and recognition




Component indicator Description
AB Antenna base
AM Amplifier
AS Antenna System
AT Antenna
BA Battery, dry
BB Battery, storage
C Control box
CG Radio frequency cable transmission lines and waveguides with terminals
CM Comparator
CN Compensators, regulators
CP Computer
CR Crystal units
CU Coupling units
CV Converter (electronic)
CW Cover
CX Cord
CY Case
DY Detector, non-electronic (see CV)
DY Dynamotor unit
F Filters
G Generator (see PU)
GO Goniometer
H Headsets, handsets, head and chest sets
ID Indicator
J Junction, jack and terminal boxes
KY Keyers, coders and interrupters
LS Loudspeaker
M Microphone
MD Modulator
MK Maintenance kit
MT Meteorological apparatus
MT Mountings
MX Miscellaneous
O Oscillator
PG Pigeon articles
PH Photographic articles
PP Power pack
PU Power unit and motors
R Radio receiver
RD Recorder
RE Relay assembly
RF Radio frequency unit
RG Radio frequency cables, transmission lines and waveguides
RL Reel assembly
RT Receiver and transmitter
S Shelter
SA Switching assembly
SB Switchboard
SN Synchroniser
T Radio transmitter
TA Telephone apparatus
TD Timing device
TH Telegraph apparatus
TK Tool kits
TS Test and measuring apparatus
TT Teletypewriter and wire facsimile apparatus
U Unions, plugs, sockets, connectors, etc.
UG Unions, plugs, sockets, connectors, etc. designed for radio frequencies
V Vehicles
VS Visual signalling apparatus