| Abbreviation | Definition |
|---|---|
| URPU | Un-Real Pop-Up |
| URT | Unique Resource Typename |
| URV | Uniform Resource Visualization |
| URV | Universal Remote Viewing |
| USA | Unicast Source Address |
| USEQ | User Queue |
| USIM | Universal Subscriber Identity Module |
| USN | Universal Sequence Number |
| USNG | United States National Grid |
| USNT | United States Network Terminal |
| USP | Uninterruptible Signal Processing |
| USRM | Universal Session Resource Manager |
| USRQ | USer ReQuest |
| USSD | Unstructured Supplementary Service Data |
| USSI | Universal Synchronous Serial Interface |
| USSN | Universal Software Solution and Networking |
| UT | Uniform Transmission |
| UTF | Unicode Transformation Format |
| UTF-8 | Unicode Transformation Format - 8 unicode characters |
| UTOPIA | Universal Test And Operations Physical Interface For Atm |