| A - Support, antenna | HD - Air conditioning apparatus | RR - Reflector |
| AM - Amplifier | ID - Indicating device | RT - Receiver and transmitter |
| AS- Antenna assembly | IL - Insulator | S - Shelter |
| AT- Antenna | IM - Intensity measuring device | SA - Switching device |
| BA - Battery, primary type | IP - Indicator, cathode-ray tube | SB - Switchboard |
| BB - Battery, secondary type | J - Junction device | SG - Generator, signal |
| BZ - Signal device, audible | KY - Keying device | SM - Simulator |
| C - Control article | LC - Tool, line construction | SN - Synchronizer |
| CA - Commutator assembly, sonar | LS - Loudspeaker | ST - Strap |
| CB - Capacitor bank | M - Microphone | T - Radio and radar transmitter |
| CG - Cable & transmission line, r.f. | MD - Modulator | TA - Telephone apparatus |
| CK - Crystal kit | ME - Meter, portable | TD - Timing device |
| CM - Comparator | MK - Maintenance kit or equipment | TF - Transformer |
| CN - Compensator | ML - Meteorological device | TG - Positioning device |
| CP - Computer | MT - Mounting | TH - Telegraph apparatus |
| CR - Crystal | MX - Miscellaneous | TK - Tool kit or equipment |
| CU - Coupling device | O - Oscillator | TL - Tool |
| CV - Converter | OA - Operating assembly | TN - Tuning unit |
| CW - Cover | OS - Oscilloscope, test | TS - Test equipment |
| CX - Cord | PD - Prime driver | TT - Teletypewriter and facsimile
apparatus |
| CY - Case | PF - Fitting, pole | TV - Tester, tube |
| DA - Antenna, dummy | PG - Pigeon article | U - Connector, audio and power |
| DT - Detecting head | PH - Photographic article | UG - Connector, r.f. |
| DY - Dynamotor | PP - Power supply | V - Vehicle |
| E - Hoist assembly | PT - Plotting equipment | VS - Signaling equipment, visual |
| F - Filter | PU - Power equipment | WD - Cable, two-conductor |
| FN - Furniture | R - Radio and radar receiver | WF - Cable, two conductor |
| FR - Frequency measuring device | RD - Recorder and reproducer | WM - Cable, multiple-conductor |
| G - Generator | RE - Relay assembly | WS - Cable, single conductor |
| GO - Goniometer | RF - Radio frequency component | WT - Cable, three-conductor |
| GP - Ground rod | RG - Cable and transmission line,
bulk r.f. | ZM - Impedance measuring device |
| H - Head, hand, and chest set | RL - Reel assembly | |
| HC - Crystal holder | RP - Rope and twine | |