Glossary - T
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
T-1 - A type of high-speed digital data connection that operates at 1.54Mbps and requires a two-pair (four-wire) connection between the telephone company Central Office and the customer premises. See also Fractional T-1.
T-carrier system - A digital transmission system that takes analog voice circuits and converts them to digital form for transmission using time division multiplexing, the T-0carrier system was designed to operate at different rates, known as T1 (1.544Mbps, equivalent to 24 channels); T2 (6.312 Mbps, equivalent to 96 channels); T3 (44.736Mbps, equivalent to 672 channels); and T4 (274.176Mbps, equivalent to 4,032 channels). (Without compression, a 64-Kpbs channel carries a single voice conversation.) Carrier systems are not always channelized; the entire system can be used to carry high-bandwidth communications.
Take Rate - The ratio of homes that pay for a cable service to homes passed.
Tap - A tap is a device which splits off a portion of the feeder line signal for the subscriber.
Tariff - A set rate and service schedule established by agreement between the phone company and a government-run regulatory agency, called the Public Utilities Commission.
Tearing - A term used to describe a picture condition in which groups of horizontal lines are displaced in an irregular manner. Caused by lack of horizontal synchronization.
Telco - A local exchange telephone carrier.
Telecommunications - Communicating over a distance through wire, radio, optical or other electromagnetic means.
Teledensity - Teledensity refers to the number of telephone lines (including wired residential and business lines) per 100 people, a rough measure of the ubiquity of the public switched telephone network (PSTN) in a country.
Teletext - Broadcast service using several otherwise unused scanning lines (vertical blanking intervals) between frames of TV pictures to transmit information from a central database to receiving television sets.
Television - The electronic transmission and presentation of pictures and sounds.
Television Households - A household having one or more television sets. Estimates for each county are based on an updating of ARB (American Research Bureau) TV penetration estimates. The number of households that watch television in any locality during prime-time hours determines the top 100 markets for FCC cable rules.
Television Market - A city or complex of closely associated cities served by commercial television broadcast signals from one or more TV stations located within the area. The FCC uses television markets for designating what kind of cable services an operator should provide in terms of signal carriage and nonbroadcast channel use.
Television Receiver-Only (TVRO) - The receiving antenna dish, or complete package or dish receiver.
Telnet - A TCP/IP protocol which allows terminal-type login access to computers on the Internet for the purpose of entering remote commands. The protocol name is capitalized; when used in the form "telnet", it refers to the client software that implements the protocol, or the act of using the protocol.
Terminal - Generally, connection point of equipment, power or signal. Any "terminating" piece of equipment such as computer terminal.
Terminator - A resistive load for an open coaxial line to eliminate reflections; usually capacitively coupled to avoid shorts in cable-powered systems.
Thickwire - Half-inch diameter coax cable.
Thinwire - Thin coaxial cable similar to that used for television/video hookups.
Threshold - The minimum level at which a signal of any kind can be detected, either by the human senses or by using any electronic instrument.
Throughput - The speed at which the data is received. Throughput can be increased by compressing data before it is transmitted, then decompressed when it is received, or by using a more efficient transmission protocol.
Tiered Programming - A group of programs for which the customer is charged a fee. For example, most cable systems offer a satellite programming tier.
Tiering - Supplying cable subscribers with one or more program services beyond the basic offerings at an extra charge. Each additional price increment is called a tier.
Tilt - Maximum difference in transmission gain of a cable television system over a given bandwidth (typically the entire forward operating frequency range).
Token - The character sequence or frame, passed in sequence from node to node, to indicate that the node controlling it has the right to transmit for a given amount of time.
Token Ring - Developed by IBM, this 4 or 16 Mbps network uses a ring topology and a token-passing access method.
Top 100 Market - Ranking of largest television broadcast areas by size of market; i.e., number of viewers and TV households. Used in FCC rulemaking and in selling of airtime to advertisers.
Topology - The arrangement of the nodes and connecting hardware that comprises the network. Types include ring, bus, star and tree.
Total Activity Report (TAR) - A quarterly Nielsen report which lists all the television activity during a sweep including broadcast stations, basic cable, pay cable, and superstations. It shows household rating and share delivery by daypart in both the DMA (total market) and cable household universe for all program sources.
Transceiver - A combination of a transmitter and a receiver having a common frequency control and usually enclosed in a single package. Extensively used in two-way radio communications at all frequencies.
Transducer - A device that converts one form of energy or disturbance into another. Transducers convert AC and DC into sound, radio waves, or other forms.
Transistor - A semiconductor device consisting of three or four layers used for switching or amplification at frequencies ranging from direct current to ultra-high.
Translator - Relay system that picks up distant television signals, converts the signals to another channel to avoid interference, and retransmits them into areas that the original television signal could not reach.
Transmission Medium - The material on which information signals may be carried; e.g., optical fiber, coaxial cable, and twisted-wire pairs.
Transponder - The part of a satellite that receives and transmits a signal.
Trunk - An analog or digital connection from a circuit switch which carries user media content and may carry telephony signaling (MF, R2, etc.). Digital trunks may be transported and may appear at the Media Gateway as channels within a framed bit stream. Trunks are typically provisioned in groups, each member of which provides equivalent routing and service.
Trunk Amplifiers - The amplifiers along the trunk line responsible for maintaining signal strength must have low distortion, low noise, and moderate gain. Degradation of the signal along the trunk cannot be corrected downstream, in fact, cascade amplifiers with similar faults simply amplify the fault too. Trunk amplifiers compensate for cable losses with automatic slope control (ASC) and automatic gain control (AGC).
Trunk Cable - Cables that carry the signal from the headend to groups of subscribers. The cables can be either coaxial or fiber depending on the design of the system.
Trunk Circuit - A circuit, part of a switching system, associated with the connection of a trunk to the switching system. It serves to convert between the signal formats used internally in the switching system and those used in the transmission circuit, and it performs logic and sometimes memory functions associated with supervisors.
Trunk Line - The major distribution cable used in cable television. It divides into feeder lines which are tapped for service to subscribers.
Trunking - Transporting signals from one point (an antenna site for instance) to another point (such as a headend), usually without serving customers directly. Trunking can be accomplished using coaxial cable, fiber optics or microwave radio.
TV Penetration - The percentage of homes having one or more television sets at the time of the ARB (American Research Bureau) survey. The ARB surveys local markets from October through July; the number of surveys in a year depends on the size of the market.
Twisted Pair - A pair of wires used in transmission circuits and twisted about one another to minimize coupling with other circuits. Paired cable is made up of a few to several thousand twisted pairs.
Two-Way Capacity - A cable television system with two-way capacity can conduct signals to the headend as well as away from it. Two-way or bi-directional systems now carry data; they may eventually carry full audio and video television signals in either direction.
Two-Way System - The ability to receive TV programming through the Broadband network and send information back through the same network. This capability is used by customers to order movies and music and to interact in other manners with the Broadband network.
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