| Abbreviation | Definition |
|---|---|
| TWT | Time Warner Telecom |
| TXE | Transmitter Empty |
| TXM | Transmission |
| TXS | Telephone eXchange Strowger |
| TZT | Tianjin Zhongtian Telecommunication |
| UA | Universal Access |
| UAC | Uniform Annual Charge |
| UAN | Universal Access Number |
| UAN | Universal Area Network |
| UART | Universal Asynchronous Receiver/Transmitter |
| UAS | Un-Available Seconds |
| UASL | Unified Access Service License |
| UAT | Universal Access Transceiver |
| UAT2 | User Acceptance Testing 2 |
| UAX14 | Unit Automatic eXchange type 14 |
| UBI | Usage Billing Information |
| UBL | Universal Bluetooth Link |
| UBT | Universal Backend Tester |
| UCB | Universal Call Blocking |
| UCC | Universal Connectivity Charge |