| Name | Notes | | 2G | second-generation mobile telephone | |
| 2.5G | Enhanced 2G mobile telephone | |
| 3G | third-generation mobile telephone | |
| ADSL | Asymmetric Digital Subscriber Line | |
| ANI | Automatic Number Identification | US |
| CID | Caller ID | |
| CLI | Caller Line Identification | Europe |
| CLID | Caller Line ID | UK |
| CTI | Computer telephony integration | |
| DDI | Direct Dialing In | |
| DECT | Digital Enhanced Cordless Telecommunications | |
| DID | Direct Inward Dialing | |
| DNIS | Dialed Number Identification System | US |
| DSL | Digital Subscriber Line | |
| DTMF | dual-tone multi-frequency | |
| GPRS | General Packet Radio Service | |
| GSM | Global system for mobile communications | |
| ISD | International subscriber dialling | UK and India |
| ISDN | Integrated Services Digital Network | |
| IVR | interactive voice response | |
| PABX | Private Automatic Branch eXchange | Europe |
| PBX | Private Branch eXchange | US |
| POTS | plain old telephone service | |
| PSTN | Public Switched Telephone Network | |
| REN | ringer equivalency number | |
| SMS | Short Message Service or text messages | |
| STD | Subscriber trunk dialling | UK and India |
| TAPI | Telephony Application Programming Interface | |
| WAP | Wireless Application Protocol | |
| WATS | Wide Area Telephone Service | US |
| VOIP | Voice over Internet Protocol | |