Hybrid Fiber/Coax(ial [cable]) (HFC)
HFC system is a broadband bi-directional shared media transmission system using fiber trunks between the headend and the fiber nodes, and coaxial distribution from the fiber nodes to the customer locations.
In Cable Television systems, this refers to a system that incorporates lightwave transmission on optical fibers for a part of the system, and extends the plant on RF broadband coaxial cables for distribution and connection to subscribers. [Arr11]
Increase in fiber connector attenuation that occurs when hydrogen diffuses into the glass matrix and absorbs some light. [Fib111]
The band of cable television frequencies above 300 MHz. [Arr11]
HyperText Markup Language (HTML)
The language used to create and display Web documents. It uses “tags” to identify the components of a document (text, graphics, and multimedia) and how those components should behave.
HyperText Transfer Protocol (HTTP)
The standard for exchanging files (text, graphics, and multimedia) on the World Wide Web. Or HTTP is the transport layer for HTML documents over the Internet Protocol (IP).
HyperText Transfer Protocol Secure (HTTPS)
An extension of HTTP developed by Netscape to enable security on a Web site. HTTPS encrypts and decrypts your page requests and the data returned to you by a Web server.
Internet Assigned Numbered Authority
INTELSAT Business Services [Sat07]
Internet Control Message Protocol
The Iconoscope is one of the first television “cameras” developed by Russian inventor Vladimir Zworykin in the early days of television. This early camera tube was equipped for rapid scanning and information storing of the photoactive mosaic that was to become the television broadcast. Equipped with the iconoscope and a cathode ray tube, Zworykin and RCA officially launched the television industry in 1931. [Glo07]
Insulation Displacement Connector. Connector installed in Antec RMT II and Antec PowerTap to connect and terminate twisted pair wires. [Arr11]
Interactive Digital Cable Ready
Interactive Digital Cable Product
ISDN Digital Subscriber Line
International Electrotechnical Commission
Institute of Electrical and Electronics Engineers; a technical professional association that contributes to voluntary standards in technical areas ranging from computer engineering, biomedical technology and telecommunications, to electric power, aerospace and consumer electronics, among others. [Fib111]
IEEE 802.3ah OAM
Gigabit Ethernet (GbE) PON (GEPON) operational, administration and maintenance (OAM); as Ethernet moved from an enterprise-centric technology into a wide area network (WAN) and access technology, designers needed to bring carrier-class capabilities to Ethernet designs. One of the most important characteristics of a carrier-class technology is the implementation of operational, administration and maintenance (OAM) management capabilities. While management capabilities were available for enterprise-class Ethernet networks, these same capabilities prior to calendar year 2005 had not been available for WAN and access Ethernet networks. Recognizing this need, the IEEE 802.3 CSMA/CD Working Group (the Ethernet standards body), through its Ethernet in First Mile (802.3ah) task force, defined a set of OAM capabilities for Ethernet links.1 These capabilities were introduced gracefully to ensure backward compatibility with existing Ethernet implementations, while still providing advanced monitoring functionality as required in public networks. The OAM work of the IEEE 802.3ah task force addressed three key operational issues when deploying Ethernet across geographically disparate locations: (1) link monitoring, (2) fault signaling, and (3) remote loopback. Link monitoring introduces some basic error definitions for Ethernet so entities can detect failed and degraded connections. Fault signaling provides mechanisms for one entity to signal another that it has detected an error. Remote loopback, which is often used to troubleshoot networks, allows one station to put the other station into a state whereby all inbound traffic is immediately reflected back onto the link. [EET04]
IEEE, IEEE 802.3ah Draft P802.3ah/D3.3, "Amendment: Media Access Control Parameters, Physical Layers and Management Parameters for Subscriber Access Networks," April 2004.
An electronics standard for connecting devices to a personal computer or set-top box. IEEE-1394 provides a single plug-and-socket connection on which up to 63 devices can be attached with data transfer speeds up to 400 Mbps (megabits per second). The standard describes a serial bus or pathway between one or more peripheral devices and a host's microprocessor. Also known as Firewire or i.Link.
Internet Engineering Task Force
Intermediate frequency. A frequency to which a signal is converted for ease of handling. Receives its name from the fact that it is an intermediate step between the initial and final conversion or detection stages. [Arr11] Superheterodyne architecture radio receivers typically employ one or more IF stages, whereas Zero-IF radio receivers do not employ IF stages.
International Frequency Registration Board of the ITU - International Telecommunications Union; regulates the allocation of satellite orbital locations. [Sat07]
Insulated-Gate Field-Effect Transistor; a type of field-effect transistor having one or more semiconductor gate electrodes. [Fre11]
Internet Group Management Protocol
Interferometric Intensity Noise [Fib111]
Internet Key Exchange
Incumbent Local Exchange Carrier
The Image Dissector was invented by Philo Farnsworth in the early days of television development. Essentially, based on the charge it collected, the device was able to recreate an image placed in front of it. It was an important step in the development of signal transfer for television devices, but was a poor conductor and needed very high light levels to work properly. [Glo07]
The total opposition a circuit, cable or component offers to alternating current. It includes both resistance and reactance and is generally expressed in Ohms. [Arr11]
A condition whereby the impedance of a particular circuit, cable or component is the same as the impedance of the circuit, cable or component to which it is connected. [Arr11]
Short bursts of high-level noise such as that resulting from the coupling of transients into a channel. Typical sources of such noises are lightning and transients from switching systems. Impulse noise, which sounds like a click, is not particularly detrimental to voice communications, but it can be detrimental to data communications. Also known as noise characterized by non-overlapping transient disturbances.
A service that allows a user to order and receive pay-per-view content in near real-time. Current pay-per-view models require that the user make arrangements to purchase the content prior to its reception.
The angle between the orbital plane of a satellite and the equatorial plane of the earth. [Sat07]
Incremental Related Carriers (IRC)
A method of spacing National Television Systems Committee (NTSC) television channels on a cable television system in which all channels except 5 and 6 correspond to the standard channel plan, used to reduce composite triple beat distortions.
Incumbent Local Exchange Carrier (ILEC)
This term refers to traditional local telephone companies such as one of the Regional Bell Operating Companies (RBOCs) in the United States.
A TV station that has no exclusive affiliation which obliges it to carry programs from one of the national networks. Individually-owned and operated cable television system, not affiliated with a Multiple System Operator.
Individually owned and operated cable television system, not affiliated with an MSO.
Index of Refraction
The ratio of the velocity of light in free space to the velocity of light in a fiber material. Always greater than or equal to one. Also called refractive index.
n = C/V
C = The speed of light in a vacuum.
V = The speed of the same wavelength in the fiber material. [Fib111]
Index Matching Fluid
A fluid whose index of refraction nearly equals that of the fibers core. Used to reduce Fresnel reflection loss at fiber ends. Also known as index-matching gel. [Fib111]
Index Matching Material
A material, often a liquid or cement, whose refractive index is nearly equal to an optical element index. Material with an index nearly equal to that of an optical fiber’s core is used in splicing and coupling to reduce reflections from the fiber end face. [Arr11]
A characteristic of an optical fiber which describes the way its index of refraction changes with its radius. [Arr11]
The ability of a device to store energy in the form of a magnetic field.
An electronic component designed to provide a controlled amount of inductance.
Industry Standard Architecture (ISA)
An interface standard for connecting hardware expansion cards to a computer. The typical ISA connection is a slot, or edge-card connector, on the computer's motherboard allowing devices such as sound cards and telephone modems to be plugged in to the computer.
A commercial, usually 90 seconds or more in length, designed to supply information about a product or service rather than to present a specific sales message.
Electromagnetic radiation with wavelength between 0.7 micrometer and about 1 millimeter. Wavelengths at the shorter end of this range are frequently called "near" infrared, and those longer than about 20 micrometers, "far" infrared. [Arr11]
Infrared Emitting Diode
LEDs that emit infrared energy (830 nm or longer). [Fib111]
Optical fibers with best transmission at wavelengths of 2 mm or longer, made of materials other than silica glass. See also fluoride glasses. [Fib111]
Indium Gallium Arsenide; generally used to make high-performance long-wavelength detectors. [Fib111]
Indium Gallium Arsenide Phosphide; generally used for long-wavelength light emitters. [Fib111]
A condition where unwanted RF signal leaks into a distribution system. [Lin07]
An erbium doped fiber amplifier (EDFA) or other type of amplifier placed in a transmission line to strengthen the attenuated signal for transmission onto the next, distant site. In-line amplifiers are all-optical devices. [Fib111]
In-Line Amplifier Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/i
A network device designed to compensate for the frequency/ loss characteristics of a coaxial cable, so as to permit the system to pass all frequencies in a uniform manner.
Excerpt from ANSI/SCTE 87-1 2008,
“Graphic Symbols For Cable Systems Part 1: HFC Symbols”
housing, for amplifiers or other cable television components, designed for use without jumper cables; cable connectors on the ends of the housing are in line with the coaxial cable.
The International Maritime Satellite Organization operates a network of satellites for international transmissions for all types of international mobile services including maritime, aeronautical, and land mobile. [Sat07]
Indium Phosphide; a semiconductor material used to make optical components, including lasers, photodetectors, and transimpedance amplifiers.
A signal (or power) which is applied to a piece of electric apparatus or the terminals on the apparatus to which a signal (or power) is applied. [Arr11]
Insertion Loss (IL)
A measure of the attenuation of a device by determining the output of a system before and after the device is inserted into the system; the loss of signal level in a cable path caused by the insertion of a passive device. [Arr11]
Institute of Electrical and Electronics Engineers (IEEE)
A voluntary organization which, among other things, sponsors standards committees and is accredited by the American National Standards Institute (ANSI). For more information, refer to www.ieee.org .
Institute of Radio Engineers (IRE)
A professional organization which existed from 1912 until January 1 1963, when it merged with the American Institute of Electrical Engineers (AIEE) to form the Institute of Electrical and Electronics Engineers (IEEE). [Wik101]
^ IEEE History Center: A Brief History of IEEE, Institute of Electrical and Electronics Engineers, USA. Retrieved on 10-06-2010.
Institute for Telecommunications Sciences (ITS)
ITS is the research and engineering branch of the National Telecommunications and Information Administration (NTIA), a part of the U.S. Department of Commerce (DOC). For more information, refer to http://www.its.bldrdoc.gov/
Institution of Electrical Engineers (IEE)
A network that is operated in conjunction with a cable TV system and which is designed to satisfy the needs of schools, businesses, or government.
A material having dielectric properties which is used to separate close electric components such as cable conductors and circuit components. [Arr11]
The insulator keeps the pin section of the terminal centered in the entry barrel of a connector. [Arr11]
Integral Mandrel (Integral Sleeve)
The function of this sleeve is to support the aluminum sheath of the cable. As the ferrule closes down to grip the sheath, the sleeve maintains the size and shape of the aluminum sheath. If the sheath were to crush down unsupported, mechanical and electrical problems could occur. [Arr11]
A circuit whose connections and components are fabricated into one integrated structure on a certain material such as silicon, gallium arsenide (GaAs), indium phosphide (InP), or gallium nitride (GaN).
Integrated Detector/Preamplifier (IDP)
A detector package containing a PIN photodiode and transimpedance amplifier. [Fib111]
Integrated Services Digital Network (ISDN)
ISDN is a digital telephone line that can be used for voice, fax, and data communications like a regular telephone line, but can transport data five times faster (or more) than a 28.8Kbps V.34 modem and allow you to talk on the phone to one person while sending data to another.
Integrated Services Digital Network User Part (ISUP)
ISUP is a protocol within the Signaling System Number 7 (SS7) suite of protocols that is used for call signaling within an SS7 network.
A way to ensure that information is not modified except by those who are authorized to do so.
The International Telecommunications Satellite Organization operates a network of satellites for international transmissions. [Sat07]
The square of the electric field strength of an electromagnetic wave. Intensity is proportional to irradiance and may get used in place of the term “irradiance” when only relative values are important. [Fib111]
Intensity information is part of a television broad cast signal. The intensity information sent to televisions tells the electron beam how bright or dim a group of phosphors need to be for the image to be viewed properly. This is essential for proper reconstruction, and also helps with color construction as it tells the electron beams the proper intensity for each color. Without intensity information, all the blues on a screen would be the same color and intensity, as would all the reds, etc. [Glo07]
In optical communications, a form of modulation in which the optical power output of a source varies in accordance with some characteristic of the modulating signal. [Fib111]
Cable systems that have the technical ability to let subscribers communicate directly from their television sets with a computer at the system headend using special converters and regular cable lines. Viewers are able to order movies and video games, access library information, and request sales brochures and coupons from home.
Interactive Program Guide (IPG)
A guide similar to an EPG, but with increased interactive features, such as allowing users to sort through onscreen TV listings by time, or channel, or themes, like children's shows, and program a VCR or TV directly from within the guide.
Interactive Television (ITV)
A combination of television with interactive content and enhancements. ITV provides a richer entertainment experience as well as information, blending traditional TV viewing with the interactivity of a PC. ITV features can include richer graphics, Internet access, e-mail, chat, instant messaging, home shopping, home banking, interactive games, on-demand services such as weather and financial information, pay-per-view (PPV), and video-on-demand (VOD). Or a catch all phrase for services/platforms that allow TV viewers to interact with their television. Typical services might include interactive program guides and e-mail and web browsing on the TV.
Interactive Voice Response System (IVR)
The automated telephony systems we are all familiar with that direct our calls within a company or organization, e.g., “Please press one for customer service, press two for technical support, press zero for the operator.”
The ability to prevent undesired optical energy from appearing in one signal path as a result of coupling from another signal path. Also called crosstalk. [Fib111]
The ability to exchange tapes between different manufacturers' videotape recorders with no appreciable degradation of playback image.
Two or more cable systems distributing a programming or commercial signal simultaneously.
Cabinets containing connector panels that interface between outside plant cables and jumper cables leading to optoelectronic equipment. Used as access points for testing and rear-ranging outside plant fibers. [Arr11]
A method of receiving TV signals by jamming unauthorized signals but having all other signals received in the clear. Because the jamming is accomplished outside the home it does not require a set-top terminal in the home.
Inter-exchange Carrier (IC)
A communications common carrier that provides telecommunications services between Local Access and Transport Areas (LATA) or between exchanges within the same LATA.
Inter-Exchange Carrier (IEC)
A long distance phone carrier, like AT&T, MCI, or Sprint. Also referred to as an IXC.
A shared boundary defined by common physical interconnection characteristics, signal characteristics, and meanings of inter-changed signals. [Arr11]
Energy which tends to interfere with the reception of the desired signals, such as fading from airline flights, RF interference from adjacent channels, or “ghosting” from reflecting objects such as mountains and buildings.
Reception of unwanted signals is interference; smart antenna systems reject interference by nulling the unwanted signal through phase shifting; they also reduce interference to other systems by nulling the transmitted signal in the direction of the unintended receiver.
An instrument that uses the principle of interference of electromagnetic waves for purposes of measurement. Used to measure a variety of physical variables, such as displacement (distance), temperature, pressure, and strain. [Fib111]
Interferometric Intensity Noise (IIN)
Noise generated in optical fiber caused by the distributed back reflection that all fiber generates mainly due to Rayleigh scattering. OTDRs make use of this scattering power to deduce the fiber loss over distance. [Fib111]
Fiber optic sensors that rely on interferometric detection. [Fib111]
Interlaced Scanning (Interlace)
A scanning process in which each adjacent line belongs to the alternate field.
Interlacing refers to the scanning format of standard television screens. In an interlace format, the entire screen is painted with the electron beam, but in alternating lines. On the first pass the odd-numbered lines are painted, and then the beam makes a second pass to paint the even–numbered lines. In the United States, standard televisions have 525 lines of resolution and the screen is refreshed 30 times a second. This means an interlacing beam paints over 15,000 lines a second. [Glo07]
Inter-Local Access and Transport Area; 1. Between local access and transport areas (LATAs). 2. Services, revenues, and functions related to telecommunications that begin in one LATA and that terminate in another or that terminate outside of the LATA. [Fib111]
Inter-Local Access and Transport Area (InterLATA)
This term refers to services provided across local access and transport areas (LATAs), roughly corresponding to the concept of long-distance communication. The 1984 breakup of AT&T opened up competition for interstate calls, and most states soon allowed competition for calls between LATAs within their states. Regional Bell operating companies (RBOCs) currently are prohibited from providing inter-LATA service until they meet certain requirements related to opening their networks to competitors as detailed in the Telecommunications Act of 1996.
Intermediate Frequency (IF)
A frequency to which a signal is converted for ease of handling. Receives its name from the fact that it is an intermediate step between the initial and final conversion or detection stages. [Arr11] Superheterodyne architecture radio receivers typically employ one or more IF stages, whereas Zero-IF radio receivers do not employ IF stages.
In a receiver, an unwanted signal sometimes interacts with the desired signal. The desired signal appears to be modulated by the undesired signal.
A fiber nonlinearity mechanism caused by the power dependent refractive index of glass. Causes signals to beat together and generate interfering components at different frequencies. Very similar to four wave mixing. [Fib111]
Form of interference involving the generation of interfering beats between two or more carriers according to the frequency relationship f=nf1+/- mf2, where n and m are whole numbers (but not zero), with appropriate expansion for additional carriers. The distortion introduced when several or many carriers are passed through a nonlinear circuit. This includes the spurious signals (beats) produced as sum and difference additions of the carriers present, and the transfer or superimposition of modulating information from one carrier to another. [Arr11]
Spurious frequencies, such as sum and difference frequencies, which are the products of frequencies transmitted through a nonlinear circuit. [Arr11]
International Electrotechnical Commission (IEC)
An international standards body.
International Organization for Standardization (ISO)
An international standards body, commonly known as the International Standards Organization.
International Telecommunications Union (ITU)
A United Nations organization that establishes standards for telecommunications devices, like ISDN hardware, modems, and Fax machines. ITU standards include J.112, J.122, H.323, V.90, X.25, and X.500. ITU is a civil international organization, headquartered in Geneva, Switzerland, established to promote standardized telecommunications on a worldwide basis. The ITU-R and the ITU-T are committees under the ITU, which is recognized by the United Nations as the specialized agency for telecommunications. [Fib111] http://www.itu.int/
A series of interconnected local, regional, national and international networks linked using the Internet Protocol. The Internet is accessible via telephony wires, HFC networks and by satellite.
Internet Assigned Numbered Authority (IANA)
The entity responsible for assigning numbers in the Internet Suite of Protocols.
Internet Control Message Protocol (ICMP)
An internet network layer protocol.
Internet Engineering Task Force (IETF)
A body responsible for, among other things, developing standards used in the Internet. Or a cooperative consortium that standardizes internet protocols, naming and other communications issues.
Internet Group Management Protocol (IGMP)
A network-layer protocol for managing multicast groups on the Internet.
Internet Key Exchange (IKE)
A method standardized by the IETF for exchanging security keys.
Internet Protocol (IP)
The computer network protocol (analogous to written and verbal languages) that all machines on the Internet must know so that they can communicate with one another. IP is a layer 3 (network layer) protocol in the OSI model. The vast majority of IP devices today support IP version 4 (Ipv4) defined in RFC-791, although support for IP version 6 (Ipv6, RFC-2460) is increasing.
Internet Protocol Security (IPsec)
A collection of Internet standards for protecting IP packets with encryption and authentication.
Internet Service Provider (ISP)
A company that sells Internet access.
Internet Signaling Transport Protocol (ISTP)
A PacketCable protocol used by PacketCable PSTN Signaling Gateways.
Inter Satellite Link - ISL
Radio or optical communications links between satellites. They serve to interconnect constellations of satellites. [Sat07]
The international entity formed by the Soviet Union to provide international communications via a network of Soviet satellites. [Sat07]
Intersymbol Interference (ISI)
1) In a digital transmission system, distortion of the received signal, manifested in the temporal spreading and consequent overlap of individual pulses to the degree that the receiver cannot reliably distinguish between changes of state, i.e., between individual signal elements. At a certain threshold, intersymbol interference will compromise the integrity of the received data. Intersymbol interference may be measured by eye patterns. [Fib111]
Interval Usage Code
A field in MAPs and UCDs to link burst profiles to grants.
Intra-Local Access and Transport Area (IntraLATA)
In the U.S., this term refers to providing services within a local access and transport area (LATA). Regional Bell operating companies (RBOCs) are permitted only to provide intraLATA service; most states allow other carriers to compete with RBOCs within LATAs.
Splice losses arising from differences in the fibers being spliced. [Fib111]
Also, see noise, intrinsic. [Arr11]
Internet Protocol; a standard protocol, developed by the USA Department of Defense (DOD), for use in interconnected systems of packet-switched computer communications networks. [Fib111]
An amplifier’s 1 dB input compression point in dBm, and defined as the input level that produces an output 1 dB lower than it should be for linear operation. The output and input 1 dB compression points are related by IP1dB = OP1dB - Gain + 1. See Mathematical Definitions and Derivations for more information.[Ard11]
A number that uniquely identifies a computer on the Internet to other host computers, used to route data packets to their intended destination. IP version 4 addresses are 32-bits in length and are displayed as four numbers (each in the range 0-255) separated by dots (e.g., 220.127.116.11). In contrast, IP version 6 addresses are 128-bits in length and can be displayed as eight hexadecimal numbers (in the range 0-FFFF) separated by colons (e.g. FEDC:BA98:7654:3210:FEDC:BA98:7654:3210).
A WindowsNT command prompt utility that displays the computer's TCP/IP configuration. It also allows a computer user to manually release and renew their IP address lease.
Individual Program Data Records