T-1
A leased-line connection capable of carrying data at 1,544,000 bits-per-second. At maximum theoretical capacity, a T-1 line could move a megabyte in less than 10 seconds. That is still not fast enough for full-screen, full-motion video, for which you need at least 10,000,000 bits-per-second. T-1 is the fastest speed commonly used to connect networks to the Internet.

T-3
A leased-line connection capable of carrying data at 44,736,000 bits-per-second. This is more than enough to do full-screen, full-motion video.

Tape Backup
Refers to the storage device commonly used by web hosting companies to backup clients' data. Tape backup is a relatively economical way of backing up data for most businesses.

TCL
Tool command language. Simple scripting language and library often used for GUI, string-manipulation, testing, and integration of multiple components.

TCP/IP
Transmission Control Protocol/Internet Protocol. This is the suite of protocols that defines the Internet. Originally designed for the UNIX operating system, TCP/IP software is now available for every major kind of computer operating system. To be truly on the Internet, your computer must have TCP/IP software.

Telnet
The command and program used to login from one Internet site to another. The telnet command/program gets you to the login: prompt of another host.

Terabyte (TB)
1024 gigabytes

Terminal
A device that allows you to send commands to a computer somewhere else. At a minimum, this usually means a keyboard and a display screen and some simple circuitry. Usually you will use terminal software in a personal computer - the software pretends to be (emulates) a physical terminal and allows you to type commands to a computer somewhere else.

Terminal Server
A special purpose computer that has places to plug in many modems on one side, and a connection to a LAN or host machine on the other side. Thus the terminal server does the work of answering the calls and passes the connections on to the appropriate node. Most terminal servers can provide PPP or SLIP services if connected to the Internet.

Third Level Domain
The next highest level of the hierarchy underneath the second level domains. Also known as subdomain. In a domain name, that portion of the domain name that appears two segments to the left of the top-level domain. For example, the webhosting in webhosting.top10cheapwebhosting.com

TIA
Telecommunications Industry Association. Another telecommunications standards organization.

Top Level Domain
A Top Level Domain (TLD) is the uppermost in the hierarchy of domain names. For example, communitech.net is our domain name. The "net" is considered the TLD and the "communitech.net" is considered the second level domain. Together they form a domain name which is unique.

There are two types of TLDs. The most common type is the Generic or Global TLDs which include .COM, .NET, .ORG, .MIL, .INT and .EDU. There is a possibility that new gTLDs will be introduced in the near future. National or ccTLDs are two letter country code domains that are managed by a registry designated and controlled by each specific country. Each registry might have differing prices, residency requirements and structure.

Traceroute
A computer program that lists network hosts visited by a packed on the way to its destination. Very useful for network debugging.

Trademark
As it relates to domain names... a word, phrase or slogan used to identify and distinguish the source of the goods or services. Trademark law may be different worldwide. If someone registers a domain name such as microsoft.to then Microsoft would need to go to the courts in Tonga to fight to get the name back. Expensive international litigation is one reason why it is important to protect your trademarks before someone else registers the names.

Traffic
Data packets being transmitted over a network.

Transfer
On occasion, domains are sold to another organization or sometimes the name of a company might change. Most registries require a letter of permission from the old owner to hand over control to the new owner. The procedures for Transfer of ownership will depend on the registry.

Transfer is also commonly used by web hosting companies to refer to bandwidth.