T1 line - A telephone line connection for digital transmission that can handle 24 voice or data channels at 64 kilobits per second, over two twisted pair wires.

T3 line - A connection made up of 28 T1 carriers, used to transmit digital signals on fiber-optic cable at 44.736 megabits per second. T3 can handle 672 voice conversations or one video channel.

tamper detection - mechanism ensuring that data received in electronic form has not been tampered with; that is, that the data received corresponds entirely with the original version of the same data.

tape backup - Storage device designed to backup onto magnetic tape all the data on a hard disk at high speeds.

Taskbar - Area of the Desktop that contains the Start Button, Task Buttons, Quick Launch Toolbar, Notification Area and Clock.

Task Buttons - Located on the Taskbar, these buttons represent open windows, minimized windows and running applications.

TCP/IP (See "Transmission Control Protocol/Internet Protocol")

telnet - TCP/IP function that allows you to directly connect to other computers on the Internet.

thin film transistor [TFT] - A component of high-performance active matrix LCDs, in which transistors are built into each pixel within the screen.

third-party cookie - (See "foreign cookie")

thread - A specific conversation topic in a newsgroup.

three-finger salute - The keyboard combination that forces a reboot on machines that support such a feature. The process is initiated by holding down the CTRL and ALT keys, then pressing the DEL key and releasing all three. In Windows 9x and higher, it will bring up the "Close Window" box to allow you to close an erratic program.

throughput - The rate at which a processor can work expressed in instructions per second or jobs per hour or some other unit of performance. The amount of data a communications channel can carry, usually in bytes per second.

thumb drive - USB flash drive

TIFF (Tagged Image File Format) - is a container format for storing images, including photographs and line art. TIFF is a flexible and adaptable file format. It can handle multiple images and data in a single file through the inclusion of "tags" in the file header. Tags can indicate the basic geometry of the image, such as its size, or define how the image data is arranged and whether various image compression options are used.

toolbar – a group of buttons that perform common tasks. A toolbar for Internet Explorer is normally located below the menu bar at the top of the form. Toolbars may be created by Browser Helper Objects.

track - One of several concentric rings on a floppy or hard disk.

trackball - A mouse-like device designed for small work areas which has a ball that is moved by the operator.

tracking cookie - any cookie that is shared among two or more Web pages for tracking a user's surfing history.

trackware - separate from Data Miners in that it is passive in nature. This category can and does include content such as tracking cookies and those that collect only anonymous information like sites visited and does not include personally-identifiable information.

Transmission Control Protocol/Internet Protocol [TCP/IP] - A set of computer-to-computer communi-cations protocols which permit computers using different operating systems (MAC, DOS, UNIX, etc.) to talk to each other.

Trojan – by analogy to the wooden horse the Greeks reputedly used to break the siege of Troy, the term Trojan is applied to programs that do something their programmers intended but that the user would not approve of if he knew about it.

trust - Confident reliance on a person or other entity. In the context of public-key infrastructure (PKI), trust usually refers to the relationship between the user of a certificate and the certificate authority (CA) that issued the certificate.

TSR {tee-ess-ar} [Terminate and Stay Resident] - A kind of DOS utility that, once loaded, stays in memory after it is terminated, and can be instantly reactivated by pressing a hotkey or combination of keys. The utility will display on top of the current screen, which will return after exiting the utility.

turbo - Switch on the front of older personal computers that allows the user to slow down the computer. Originally, it was a board used to speed-up an 8088 from 4.77 to 8 or 10 MHz.

twisted pair cable - Type of cable used for some network wiring. It has pairs of copper wires twisted together, to minimize electrical noise. There are shielded twisted pair (STP) and unshielded twisted pair (UTP) cables.