| Abbreviation | Definition |
|---|---|
| EC | Echo Cancelling |
| EC | Enhanced Cellular |
| EC | Entropy Coding |
| ECA | Extended Calling Area |
| ECC | Extended Community Calling |
| ECG | English Cell Group |
| ECHI | External Call History Interface |
| ECITTC | European Committee for Information Technology Testing and Certification |
| EC-n | Electrical Carrier (n=a number, e.g., EC-4) |
| ECP | Exchange Control Panel |
| ECR | Enhanced Call Routing |
| ECS | Emergency Communication System |
| ECSA | Exchange Carriers Standards Association |
| ECT | Explicit Call Transfer |
| ECTA | European Competitive Telecommunications Association |
| ECTEL | Eastern Caribbean TELecommunications Authority |
| ECTF | Enterprise Computer Telephony Forum |
| EDC | Electronic Dispersion Compensator |
| EDD | Envelope Delay Distortion |
| EDFA | Erbium-Doped Fiber Amplifier |