Glossary - A
Access Channels - Channels set aside by the cable operator for use by the public, educational institutions, municipal government, or fore lease on a non-discriminatory basis.
Access Network - The part of the carrier network that touches the customer’s premises. The Access Network is also referred to as the local drop, local loop, or last mile.
Access Node (AN) - Part of the Access Network which performs some or all of the following: modulating forward data onto the Access Network; demodulating return-path data; enforcing the MAC protocol for access onto the Access Network; separating or classifying traffic prior to multiplexing onto the Transport Network—such as differentiating traffic that is subject to QoS guarantees from traffic that receives best-effort support; enforcing signaling; handling passive operations such as splitting and filtering.
Active Circuit - Powered circuitry containing transistors, such as amplifiers, power supplies or converters.
Ad avails - Advertising spots available to a cable operator to insert local advertising on a cable network.
Adaptive smart antenna - Combines multiple antenna elements with signal processing algorithms to optimize its radiation and/or reception pattern automatically in response to the signal environment.
Additional Call Offering (ACO) - An ISDN provisioning option that instructs the telephone company’s Central Office switch to alert a customer’s terminal adapter that a second phone call is being placed to one of the phone numbers the adapter services which is already in use. Sometimes erroneously called FCO or Flexible Call Offering.
Addressable - Able to signal from the headend or hub in such a way that only the desired subscriber’s receiving equipment is affected. In this way, it is possible to send a signal to a single subscriber and effect changes in the subscriber’s level of service.
Adjacent Channel - Any of two TV channels are considered adjacent when their view carriers, either off-air or on a cable system, are 6 MHz apart. FM signals on a cable system, two channels apart are adjacent when their carriers are 400 to 600 kHz apart.
Admitted Service Flow - A Service Flow, either provisioned or dynamically signaled, which is authorized and for which resources have been reserved but is not active.
Advanced Television System Committee (ATSC) - An organization founded in 1983 to research and develop a digital TV standard for the U.S. Or an international organization of 200 members that is establishing voluntary technical standards for advanced television systems.
Aerial Plant - Cable that is suspended in the air on telephone or electric utility poles.
Algorithm - An automatic signal-processing strategy that varies the way in which multiple antenna elements are employed as a function of operational scenarios.
Allocations - The assignments of frequencies by the FCC for various communications uses (e.g., television, radio, land-mobile, defense, microwave, etc.) to achieve fair division of the available spectrum and minimize interference among users.
Alternative access provider - A telecommunications firm, other than the local telephone company, that provides a connection between a customer’s premises to a point of presence of the long distance carrier.
American National Standards Institute (ANSI) - A US standards body.
Amplifier - A device that boosts the strength of an electronic signal. In a cable system, amplifiers are spaced at regular intervals throughout the system to keep signals picture-perfect regardless of how far you live from the headend.
Amplitude Modulation - The process of impressing information on a radio frequency signal by varying its amplitude. Generally amplitude modulation is used for the purpose of relaying messages by voices, television, facsimile or other modes.
Analog - In telecommunications, analog refers to a transmission standard that uses variable frequencies and amplitudes of electrical impulses to emulate the audio waveform of sound. An analog telephone line is referred to as a POTS line. Traditional form of telecommunications transmission in a constant variable wave, rather than in packet-based (or digital) form. See also modem and digital.
Analog Device - A device that operates with variables represented by continuously measured quantities such as voltages, resistances, rotations and pressures.
Analog Signal - A signal that is solely dependent on magnitude to express the information content.
Analog-to-Digital - A device that converts a signal whose input is information in the analog form and whose output is the same information in digital form.
Antenna - A structure or device used to receive or transmit electromagnetic waves.
Antenna Array - A group of identical antennas arranged and interconnected for achieving greater directivity (gain) or beam shaping.
Antenna Preamplifier - A small amplifier, usually mast-mounted, for amplifying weak signals to a level sufficient to compensate for down-lead losses and to supply sufficient input to system control devices.
Antenna Stack - Antenna tower with multiple antennas and supports.
Anti-Siphoning - FCC rules which prevent cable systems from “siphoning off” programming for pay cable channels that otherwise would be seen on conventional broadcast TV. “Anti-siphoning” rules state that only movies no older than three years and sports events not ordinarily seen on television can be cablecast.
Application - An application is a functional implementation realized as software running in one or spread over serveral interplaying hardware entities.
Application boundary - A concise general description of the data elements (HTML documents, code files, images, etc.) used to form one application and the logical locator of the entry point, the application boundary is described by a regular expression over the URL language. Where no such boundary is drawn, the default boundary shall be the entire set of documents that the OpenCable platform can access.
Application Information Table (AIT) - Provides information about the activation state of service bound applications.
Application Manager - The application manager is the entity in the OpenCable Application Platform that is responsible for managing the lifecycle of the applications. It manages both the bound and unbound applications.
Application Platform - An application platform is the collection of application program interfaces and protocols on which content and applications are developed.
Application Program Interface (API) - An application program interface is the software interface to system services or software libraries. An API can consist of classes, function calls, subroutine calls, descriptive tags, etc.
Aspect Ratio - The aspect ratio refers to the ratio of width to height of a picture. Standard definition television uses a 4:3 aspect ratio. High definition television uses a 16:9 aspect ratio.
Asymmetric Connection - A connection where data can flow in one direction at a much higher speed than in the other. Some examples of asymmetric connections are ADSL, 56K Modems, and satellite downlinks. See also back channel.
Asymmetric Digital Subscriber Line (ADSL) - ADSL is a data communications technology that can “piggyback” a standard voice telephone connection and a high-speed (up to 8Mbps) digital data link on to a single pair local loop connections to a customer premises. ADSL technology is an asymmetric technology, meaning that the speed of the digital link to a customer premises is generally not the same speed as the connection coming back. With ADSL, for example, a customer may have only 128Kbps of outbound bandwidth, but may be able to receive data at speeds of 8Mbps. See DSLAM, NID, and xDSL.
Asynchronous - A type of transmission in which each character is transmitted independently without reference to a standard clock; uses stop and start bits.
Audio - Relating to sound or its reproduction; used in the transmission or reception of sound.
Automatic Gain Control (AGC) - A circuit which automatically controls the gain of an amplifier so that the output signal level is virtually constant for varying input signal levels.
Availability - In cable television systems, availability is the long-term ratio of the actual RF channel operation time to scheduled RF channel operation time (expressed as a percent value) and is based on a bit error rate (BER) assumption.
Available Bit Rate (ABR) - An ATM layer service where the limiting ATM-layer transfer characteristics provided by the network may change subsequent to the connection established.
Average revenue per unit (ARPU) - Commonly used a financial benchmark in the cable industry to measure average revenue per cable subscriber.