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Wireless Networking Glossary
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| T1 | Most commonly used digital line in United States, Canada and Japan. Uses copper wire and spans major metro areas. Internet access providers connect to Internet as a POP on T1 lines owned by major telephone company networks. North American equivalent of E1 in Europe. |
| Tandem | Any switch that is used to receive and route traffic (e.g. phone calls), but neither originates nor terminates them |
| TCP/IP | Suite of many protocols that allow computers and networking devices to communicate. |
| TDM | Time-Division Multiplexing. Wide-area networking technology in which data is split, or multiplexed, into time-specific segments for transmission over a single path. The segments are then put back together, or "de-multiplexed" at other end of path. Circuit-switched network, vs. packet-switched VoIP networks. See FDM. |
| TDMA | Time Division Multiple Access. Technology used in digital cellular telephone communication; divides each cellular channel into three time slots in order to increase amount of data that can be carried. Basis for GSM. See also CDMA, Mobile Wireless. |
| Telco | Any telephone company. |
| Telnet | User command and underlying TCP/IP protocol for accessing remote/host computers. |
| Tera | Prefix to indicate one trillion (e.g. Tera-bit). Abbreviated T |
| TETRA | Terrestrial Trunked Radio. |
| Thermal Noise | Radio frequency noise associated with thermal activity. At a typical temperature of 300 degrees Kelvin (26.84 degrees Celsius), thermal noise is -174 dBm per hertz, or 114 dBm in a 1 MHz channel. |
| throughput | The actual traffic supported, as opposed to the raw bandwidth. Bandwidth that does not result in throughput may be due to packets containing errors, retransmissions, errorneous routing and many other causes. See goodput and badput |
| TIA | Telecommunications Industry Association. A trade association that, among other things, defines standards for cellular and PCS, specifically AMPS, NAMPS, CDMA and TDMA |
| TIA/EIA | A prefix for a standard produced by the TIA in association with the EIA |
| TIFF | Tagged Image File Format. Supports up to 24 bit color. Files tend to be large, but high quality. Perhaps because of the file size, it is not supported by many browsers. cf GIF, JPEG, PNG |
| Token Ring | LAN in which all computers are connected in ring or star topology. A bit or token-passing scheme is used in order to prevent collision of data between two computers that want to send messages at same time. Second most widely used protocol on local area networks after Ethernet. |
| ToS | In a QoS scheme, an eight-bit field that lets values from 0 to 15 be assigned to request special handling of traffic (for example, minimize delay, maximize throughput). Succeeded by DSCP. |
| Transceiver | Combination transmitter/receiver device. Electronic switch allows transmitter and receiver to be connected to same antenna, while preventing signal reception during transmission. Transmission and reception usually occur on same frequency. See Full Duplex, Half Duplex. |
| Transcoding | Conversion from one voice (or other media format) coder to another. Multiple transcoding operations can seriously reduce the end-to-end quality. |
| Transparent | Data that is, to lower protocol layers, simply a sequenced collection of bits. Good protocol design tries to make all protocol layers transparent to all others, although often violations of this principal are necessary |
| Transparent LAN | Transparent LAN Service. Used for data communication between remote sites. Data connection between sites appears as a LAN connection, even though sites may be widely separated. Usually implemented by tunneling egress LAN traffic at each site. Traffic will be reconstituted to its original form when it arrives at respective remote site. |
| Transparent learning bridge | Data communication device that uses Layer 2 information in its forwarding decisions. Learns location of local data devices (PCs, etc.) and subsequently only forwards traffic to port where destination device resides. |
| Transponder | Communications, monitoring, or control device that picks up and automatically responds to an incoming signal. Term is contraction of the words transmitter and responder. Can be either passive or active. |
| TTY | A device used by the deaf or hearing-impaired to communicate text messages over telephone systems. It runs at 45.45 bps. See TDD |
| Tunnel | An extra protocol addressing layer used to carry data where the inner addressing layer will not take it. Often used in IP, e.g. as part of Mobile IP or VPN |
| Tunneling | Transmission of data intended for use only within a private, usually corporate network through public network in such a way that the public network’s routing nodes are unaware that transmission is part of a private network. Allows service provider network to act as a VLAN trunk port; eliminates need for additional routers. See VLAN. |
| Twisted pair | Ordinary copper wire that connects home and business computers to telephone company. To reduce crosstalk or electromagnetic induction between pairs of wires, two insulated copper wires are twisted around each other. Alternatives are coaxial cable and fiber optic. |
| TX | Abbrevation for transmission or transmitter |