| RFID | Radio Frequency Identification Identifizierung per Funksignal, vgl. http://www.foebud.org |
| RF | Radio Frequency |
| LOWFER | Low Frequency Experimental Radio |
| RFI | Radio Frequency Interference |
| HERF | High Energy Radio Frequency |
| ERFA | European Radio Frequency Agency vgl. Brüssel, [BE], http://www.nato.int |
| VOR | Very high frequency Omnidirectional Radio range UKW-Drehfunkfeuer |
| ID | Identification |
| UID | User Identification |
| IDN | Identification Number |
| CID | Connection Identification |
| VID | Volume Identification Kennzeichnung von Datenträgern |
| SID | Station Identification |
| IFF | Identification-Friend or Foe |
| ACI | Automatic Car Identification |
| DI | Decoder Identification |
| DNI | Data Network Identification |
| NUI | Network User Identification |
| NIS | NATO Identification System |
| ONI | Operator Number Identification |
| CNIP | Calling Name Identification Presentation |
| PIR | Protein Identification Resources |
| CONP | Connected Name Identification Presentation |
| CLID | Calling Line Identification |
| CLI | Calling Line Identification |
| CIC | Carrier Identification Code |
| PID | Prozess ID [process identification] |
| CDI | Circle Digit Identification |
| OTI | Original Transmitter Identification |
| EIN | Employer Identification Number |
| PIE | Persistent Identification Element |
| FIT | Fingerprint Identification Technology |
| FID | Format Identifier/Identification |
| PI | Program Identification / Interruption |
| EUID | Effective User IDentification |
| UIC | User Identification Code |
| SID | Security Identification / Identifier |
| MID | Maritime Identification Digit |
| MIN | Mobile Identification Number |
| GID | Group Identifier/Identification |
| FIU | Fingerprint Identification Unit |
| MIS | Manipulated Identification of Spins |
| LF | Low Frequency [30-300 kHz] |
| VLF | Very Low Frequency |
| FIO | Frequency In and Out |
| eTIN | electronic Taxpayer Identification Number |
| COLP | Connected Line Identification Presentation |
| ISIN | International Securities Identification Number |
| COLR | Connected Line Identification Restriction |
| PID | Process / Protocol Identification Number |