| Word | Description |
| ULL (Unconditioned Local Loop) | The ‘raw’ copper wires that provide the connection from a telephone in the customer’s premises back to the point in the network (usually an exchange, but sometimes a kerb-side equipment cabinet) where the first electronics in the circuit are encountered. Telstra’s wholesale operation sells other carriers access to the ULLs at regulated prices. |
| Unix | A computer operating system. It does not have a 'point and click' interface that most other operating systems have; instead the user must type in specific line commands. |
| Uploading | The process of copying computer files from your own computer to a computer on the Internet. |
| URL (Uniform Resource Locator) | The address of a file or web page accessible on the Internet. |
| Usenet | A network of discussion groups on the Internet. |