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• TCP/IP:
  Acronym for Transmission Control Protocol/Internet Protocol, the suite of communications protocols used to connect hosts on the Internet. TCP/IP uses several protocols, the two main ones being TCP and IP. TCP/IP is built into the UNIX operating system and is used by the Internet, making it the de facto standard for transmitting data over networks. Even network operating systems that have their own protocols, such as Netware, also support TCP/IP.
   
• Telnet:
  One of the TCP/IP Protocols. It allows a connection to another computer over dedicated phone lines.
   
• Terabyte: (TB)
  2 to the 40th power (1,099,511,627,776) bytes. This is approximately 1 trillion bytes.
  10 to the 12th power (1,000,000,000,000). This is exactly one trillion.
   
• Terminal:
  This is what you look at when you're on the Internet. It's your computer screen.
   
• Terminator:
  A device attached to the end-points of a bus network or daisy-chain. The purpose of the terminator is to absorb signals so that they do not reflect back down the line. Ethernet networks require a terminator at both ends of the bus, and SCSI chains require a single terminator at the end of the chain.
  
  A character that indicates the end of a string. In the C programming language, the null character serves as a terminator.
   
• Terminal Emulation:
  This is an application that allows your terminal to act as a dumb terminal.
   
• Thin Client:
  Typically, a Thin Client will have little or no software installed and does not recieve its information through a hard drive but rather from servers in a network. Since a Thin Client assumes the presence of a file server, these systems cost considerably less than a fully loaded personal computer. The word "Thin" refers to the boot image that this type of system requires.
   
• Thread:
  In online discussions, a series of messages that have been posted as replies to each other. A single forum or conference typically contains many threads covering different subjects. By reading each message in a thread, one after the other, you can see how the discussion has evolved. You can start a new thread by posting a message that is not a reply to an earlier message.
   
• Throughput:
  The amount of data transferred from one place to another or processed in a specified amount of time. Data transfer rates for disk drives and networks are measured in terms of throughput. Typically, throughputs are measured in Kbps, Mbps and Gbps.
   
• Time Constant:
  In electronics, this term refers to a measured amount of time that current or voltage rises or falls across a circuit.
   
• Toggle:
  A function that allows a user to switch back and fourth between an OFF and ON position.
   
• Top Down Testing:
  Also known as "Bottom Up Testing". It exists as an incremental testing strategy to ensure that designs are correct from the very beginning. It starts by testing the user interface, while the lower hierarchy components functionality is simulated by a dummy procedure known as a "stub". The testing continues in this manor until all of the components have been tested.
   
• Topology:
  In networking, this refers to the physical or logical arrangement of a network. Physical Topology would refer to the connecting of the cables and nodes and the Logical Topology would refer to how the information flows through the network.
   
• Transceiver:
  Short for transmitter-receiver, a device that both transmits and receives analog or digital signals. The term is used most frequently to describe the component in local-area networks (LANs) that actually applies signals onto the network wire and detects signals passing through the wire. For many LANs, the transceiver is built into the network interface card (NIC). Some types of networks, however, require an external transceiver. In Ethernet networks, a transceiver is also called a Medium Access Unit (MAU).
   
• Transfer Rate:
  The speed at which a disk drive can transfer information between its platters and your CPU. The transfer rate is typically measured in megabytes per second, megabits per second, or megahertz.
   
• Transparent:
  Something that occurs without being known to the user.
   
• Transistor:
  A device composed of semiconductor material that amplifies a signal or opens or closes a circuit. Invented in 1947 at Bell Labs, transistors have become the key ingredient of all digital circuits, including computers. Today's microprocessors contains tens of millions of microscopic transistors.
  
  Prior to the invention of transistors, digital circuits were composed of vacuum tubes, which had many disadvantages. They were much larger, required more energy, dissipated more heat, and were more prone to failures. It's safe to say that without the invention of transistors, computing as we know it today would not be possible.
   
• Trojan:
  A type of computer virus that is loaded into an unsuspecting users system via a host program such as a free game. The Trojan can be programmed by the author to perform many actions once activated by the user. These actions usually have malicious intent. The term "Trojan" comes from ancient Greece, where the Greeks used a wooden horse containing hidden Greek soldiers to gain entrance to the city of Troy.
   
• True Color:
  Refers to any graphics device or software that uses at least 24 bits to represent each dot or pixel. Using 24 bits means that more than 16 million unique colors can be represented. Since humans can only distinguish a few million colors, this is more than enough to accurately represent any color image.
   
• TTL (Transistor-Transistor Logic):
  A digital electronics term used to describe a class of integrated circuits derived from two transistors.
   
• Turnkey System:
  A system that already contains all the components and programs required for operation. The vendor takes care of installation and configurations so all the user has to do is "turn the key" to begin using the system.
   
• TWAIN:
  Stands for Technology Without An Interesting Name. 

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