A single TDMA equipped earth station can extend its capacity by having access to several down-link beams by hopping from one transponder to another. In such a configuration the number of available transponders must be equivalent to the square of the number of beams that are interconnected or cross-strapped. [Sat07] Transport Layer Security (TLS)
An Internet security protocol based on SSL.
In MPEG-2, a packet-based method of multiplexing one or more digital video and audio streams having one or more independent time bases into a single stream.
A device that attenuates a selected band of frequencies in a signal. Also known as a notch filter. [Arr11] Tree
A network architecture in which transmission routes branch out from a central point. [Arr11] Trigger
A trigger is an event that may cause a change in the behavior of a DVB-HTML application that registers interest in such events. Triggers may come from many sources (for example, the broadcast stream) or may be generated from other data (such as the system clock), or may be generated as a result of user interaction. The trigger may include a reference to time, which may be absolute (UTC), relative to some other event, relative to the NPT of a media stream. It also can carry some semantically significant payload in order to affect changes in an application based on information not available at the time an application was written.
Spurious signals generated when three or more carriers are passed through a nonlinear circuit. The spurious signals are sum and difference products of any three carriers, sometimes referred to as "beats." Triple beat distortion is calculated as a voltage addition. [Arr11] Tri-Shield
A type of coaxial drop cable where the protective covering over the center conductor and dielectric and underneath the jacket consists of a foil-braid-foil combination. [Arr11] Trivial File-Transfer Protocol (TFTP)
An Internet protocol for transferring files without the requirement for user names and passwords that is typically used for automatic downloads of data and software.
Tru2way is a CableLabs brand name for an interactive television technology platform. Tru2way includes hardware and software specifications that enable cable hybrid fiber/coax networks to deliver interactive applications such as electronic program guides, interactive ads, games, chat, web browsing, and t-commerce. The brand also appears as “” and is used to market cable services, applications, and devices that support the tru2way architecture. A cable television subscriber who has an integrated digital television (DTV) that supports tru2way can enjoy the same features as those delivered by way of the cable provider's leased set-top box (STB), without the STB.
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. Also, the main distribution lines leading from the headend of the cable television system to the various areas where feeder lines are attached to distribute signals to the subscriber. [Arr11]
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).
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.
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.
The major distribution cable used in cable television. It divides into feeder lines which are tapped for service to subscribers.
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.
TS Transport Stream TSS
Telecommunications Standardization Sector; the world standards setting organization resulting from the combination of the CCITT (Consultative Committee on Telephony and Telegraphy) and the CCIR (Consultative Committee on International Radio). [Sat07] TTL
Abbreviation for transistor-transistor logic. An old logic family. [Fib111]
An IPsec (ESP or AH) mode that is applied to an IP tunnel, where an outer IP packet header (of an intermediate destination) is added on top of the original, inner IP header. In this case, the ESP or AH transform treats the inner IP header as if it were part of the packet payload. When the packet reaches the intermediate destination, the tunnel terminates and both the outer IP packet header and the IPsec ESP or AH transform are taken out.
An arrangement where all aspects of building or rebuilding a cable system are handled by a single outside entity. All design, construction, splicing, alignment and testing is under management responsibility of the entity until the total job or phase is complete and turned over to the cable system management. [Arr11] TV Everywhere
TV Everywhere is an authentication system whereby certain premium content (TV shows, movies, etc.) are available online — but only if you can prove (or “authenticate”) that you have a subscription to a multiservice operator (e.g. cable, satellite, telco TV).
The TV Everywhere moniker is from Time Warner. Up until now, Comcast had been using “OnDemand Online” for its authentication plans. [Gig11] TVHH
Television Household; standard of measurement used by audience rating companies; a home with at least one television set. [All11]
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.
TVRO Television Receiver-Only. Defines a facility which can include antennas, preamplifiers, and receivers for the reception only of television signals from a geostationary satellite in space. [Arr11]
Thermoplastic wire. [Arr11] Tweaking
The process of adjusting an electronic receiver circuit to optimize its performance. [Sat07] Twin-Lead
A transmission line having two parallel conductors separated by insulating material. Line impedance is determined by the diameter and spacing of the conductors and the insulating material and is usually 300 ohms for television receiving antennas. Also called balanced transmission line and twin-line. [Arr11] 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.
Bidirectional communications over the same communication medium.
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.
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.
Traveling Wave Tube; A microwave tube of special design using a broadband circuit in which a beam of electrons interacts continuously with a guided electromagnetic field to amplify microwave frequencies. [Sat07]