Conrad L. Young’s Wired Broadband and Related Industry Glossary of Terms with Acronyms As of 15 February 2012 Open Access This document is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial
Kevlar A very strong, very light, synthetic compound developed by DuPont which is used to strengthen optical cables
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Kevlar A very strong, very light, synthetic compound developed by DuPont which is used to strengthen optical cables. (FiberOpticsInfo) Key Distribution Center (KDC) A network service that supplies tickets and temporary session keys. Key Exchange The swapping of public keys between entities to be used to encrypt communication between the entities. Key Handling Epoch The time interval within the application processing that starts with the delivery of a user interface (UI) event to the application and ends with the notification to the platform that the application has completed all actions that may either cause the platform to forward that same key to another application, or influence how the platform will handle the subsequent key. In the case of the execution engine, this notification consists of returning from a key handling callback. Key Management The process of distributing shared symmetric keys needed to run a security protocol. Key Pair An associated public and private key where the correspondence between the two are mathematically related, but it is computationally infeasible to derive the private key from the public key. Keying Generating signals by the interruption or modulation of a steady signal or carrier. (FiberOpticsInfo) Keying Material A set of cryptographic keys and their associated parameters normally associated with a particular run of a security protocol. Keys Numeric assignments for the various calling features an ISDN adapter supports, like call drop, transfer and hold. Also called buttons, keys get their names from the various feature buttons on an advanced multi-line voice phone. Or a mathematical value input into the selected cryptographic algorithm. Keyspace The range of all possible values of the key for a particular cryptographic algorithm. kg Kilogram; approximately 2.2 pounds. (FiberOpticsInfo) kHz Kilohertz; one thousand cycles per second. (Arris Glossary of Terms) Kilo (K) Meaning one thousand. Communications and computer terminology, however, uses the term K or Kilo differently. In communications terminology, one K is equal to 1000, but when measuring computer memory or disk space, one K is equal to 1024. Kilobit One thousand bits. (Arris Glossary of Terms) Kilohertz (kHz)
KiloBits Per Second (Kbps) One Kbps is equal to 1000 bits transmitted in one second. Kinescope The Kinescope was inventor Vladimir Zworykin’s version of a cathode ray tube. Armed with a kinescope and his patented iconoscope camera tube, Zworykin and RCA spawned the birth of the television industry. (Glossary of Terms dot Net) Kinescope Recording A film recording made by a motion picture camera designed to photograph a television program directly from the front of a television tube. Often called a “kine.” Klystron The Klystron is an electron tube that makes use of velocity modulation in order to amplify or create ultra-high frequency waves. As well as being instrumental in the advent of Doppler radar (which was, in fact, the invention that helped defeat the Axis powers in World War Two) the Klystron was instrumental in the development of high frequency broadcasting, which made large-scale broadcast television possible. (Glossary of Terms dot Net) km Kilometer; 1 km = 3,280 feet or 0.62 miles. (FiberOpticsInfo) KS Adapter Adapts a housing (pin) connector to another type of connector. (Arris Glossary of Terms) KS Port Terminator Designed to terminate unused ports on distribution equipment. Terminates 60 cycle VAC and RF signals. (Arris Glossary of Terms) Ku-band The group of microwave frequencies from 12 to 18 GHz; the band of satellite downlink frequencies from 11.7 to 12.2 GHz. Ku-Band Feedhorn Equipment located at the center of a satellite antenna, used to collect Ku-band satellite downlink (11.7 to 12.2 GHz) signals and direct them into a low noise amplifier (LNA) or low noise block converter (LNB). (Arris Glossary of Terms) L:
Lambertian Emitter An emitter that radiates according to Lambert’s cosine law, which states that the radiance of certain idealized surfaces depends on the viewing angle of the surface. The radiant intensity of such a surface is maximum normal to the surface and decreases in proportion to the cosine of the angle from the normal. Given by: N = N0cosA Where: N = radiant intensity N0 = radiance normal to an emitting surface. A = angle between the viewing direction and the normal to the surface. LAN Local Area Network; a series of cable-connected work stations and computers that are linked in a limited geographical area. Usually high-bandwidth networks which connect many nodes. Distance between nodes is limited to a few kilometers. (Arris Glossary of Terms) Large Core Fiber Usually, a fiber with a core of 200 µm or more. (FiberOpticsInfo) Large Effective Area Fiber (LEAF) An optical fiber, developed by Corning, designed to have a large area in the core, which carries the light. (FiberOpticsInfo) Laser Acronym for "light amplification by stimulated emission of radiation”. A device that generates coherent electromagnetic radiation in, or near, the visible part of the spectrum. (Arris Glossary of Terms) Laser Diode A semiconductor that emits coherent light when forward biased. (FiberOpticsInfo) 
Laser Diode Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/l Laser Speckle Sparkling granular pattern that is observed when an object diffusely reflects coincident laser light. Speckle appears as an irregularity in many holographs but has been exploited as a measurement technique. (Photonics dot com) Lashing Wire Stainless steel wire used for securing coaxial cable to strand or wire rope. (Arris Glossary of Terms) Last Mile Refers to the last “mile” between a central office and a customer in a telephone network or a node and a customer in a cable television network. Last-mile distances generally range from 0 miles to 3 miles. Generally referring to the telco local loop, which is the link between the central office (CO) at the edge of the telco network and the user premises. In a broader contemporary context, the term applies to the physical connection between the edge of any service provider's network and the end user's premises. In practice, the last mile is often much longer than a mile. In the United States, UTP local loops are generally 12,000 feet or less, but often are as long as 18,000 feet. Passive optical network (PON) standards allow for local loops as long as 12 miles (20 km).Whether it is the first mile or the last mile, which is a matter of perspective, it is seldom exactly a mile. Sometimes referred to as the first mile. (Dictionary, Your Dictionary) Last Mile Framing The data encapsulation and transmission protocols used between the consumer premises and the headend. Framing techniques include ATM, MPEG and IP. LATA Local Access and Transport Area Latency The time taken for a signal element to pass through a device or system. Lateral Displacement Loss The loss of power that results from lateral displacement of optimum alignment between two fibers or between a fiber and an active device. (FiberOpticsInfo) 
Lateral Displacement Loss Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/l Latitude The measurement of a position on the surface of the earth north or south of the equator, measured in degrees of angle. (Arris Glossary of Terms) Launch Fiber An optical fiber used to couple and condition light from an optical source into an optical fiber. Often the launch fiber is used to create an equilibrium mode distribution in multimode fiber. Also called launching fiber. (FiberOpticsInfo) Layer In networks, layers refer to software protocol levels comprising the architecture, with each layer performing functions for the layers above it. Or a subdivision of the Open System Interconnection (OSI) architecture, constituted by subsystems of the same rank. Layer 2 Link layer in Open Systems Interconnection (OSI) framework Layer 3 Network layer in OSI stack; layer in firewall in which routing is based on IP address L-Band That portion of the electromagnetic spectrum from 950 to1450 MHz. (Arris Glossary of Terms) LC Connector LC stands for Lucent Connector. The LC is a small form-factor fiber optic connector. (Timbercon) 
Photo courtesy of http://www.timbercon.com/
Laser Diode LDAP Lightweight Directory Access Protocol LDS Local Distribution System LEAF Large Effective Area Fiber Leapfrogging Cable television operators' practice of skipping over one or more of the nearest TV stations to bring in a further signal for more program diversity. FCC rules establish priority for carrying stations that lie outside the cable systems service area. Leaseback The practice by telephone companies of installing and maintaining cable television distribution systems, and leasing the facilities back to separate contractors for operation of the system. Leased Access On some systems, a public access channel for which programmers pay a fee for use and are permitted to sell commercial time in their programming. Also known as Leased Channel. Least Significant Bit In a binary code, the bit or bit position assigned to the smallest quantity or increment that can be represented by the code. (FiberOpticsInfo) Leakage The undesirable passage of signal over the surface of or through an insulator. (Arris Glossary of Terms) LEC Local Exchange Carrier; a local telephone company, i.e., a communications common carrier that provides ordinary local voice-grade telecommunications service under regulation within a specified service area. (FiberOpticsInfo) LED Light emitting diode. LEDs are used in various applications ranging from being used as simple display indicators to use in fiber optics as a relatively low cost light source. (Arris Glossary of Terms) Level A measure of the difference between a quantity or value and an established reference. (Arris Glossary of Terms) Level Diagram A graphic diagram indicating the signal level at any point in the system. LEX Local Exchange; synonym for central office (CO). (FiberOpticsInfo) LGID Logical Group Identifier; the optical line termination (OLT) assigns new group identifies (LGIDs) for grouping or separating some ports from other port groups. These LGIDs can be related to the virtual local area network (VLAN) group identifiers (VIDs) or multicast address/addresses, and can be applied for link segregation or multicasting. LH Long-Haul; a classification of video performance under RS-250C. Lower performance than medium-haul or short-haul. (FiberOpticsInfo) L-I Curve The plot of optical output (L) as a function of current (I) which characterizes an electrical-to-optical converter. A typical L-I curve is shown below. (FiberOpticsInfo) 
Graph of L-I Curve courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/l LIDB Line Information Database Lifetime of an Application The lifetime of an application characterizes the time from which the application is loaded to the time the application is destroyed. Light Light or visible light is the portion of electromagnetic radiation that is visible to the human eye, responsible for the sense of sight. Visible light has a wavelength in a range from about 380 or 400 nanometers to about 760 or 780 nm, [1] with a frequency range of about 405 THz to 790 THz. In physics, the term light often comprises the adjacent radiation regions of infrared (at lower frequencies) and ultraviolet (at higher), not visible to the human eye.[2] [3] (Wikipedia)
Light-emitting Diode A semiconductor that emits incoherent light when forward biased. Two types of LED’s include edge-emitting LEDs and surface-emitting LEDs (illustrated). (FiberOpticsInfo) 
LED Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/l Light Piping Use of optical fibers to illuminate. (FiberOpticsInfo) Light Source A generic term that includes lasers and LEDs. (Arris Glossary of Terms) Lightguide Synonym for optical fiber. (FiberOpticsInfo) Lightwave Any electromagnetic radiation having a wavelength in the range from 800 to 1,600 nanometers in the near infrared region. (Arris Glossary of Terms) Also, the path of a point on a wavefront. The direction of the lightwave is generally normal (perpendicular) to the wavefront. (FiberOpticsInfo) Line or Loop An analog or digital access connection from a user terminal which carries user media content and telephony access signaling (DP, DTMF, BRI, proprietary business set). Linearity The basic measurement of how well analog-to-digital and digital-to-analog conversions are performed. To test for linearity, a mathematically perfect diagonal line is converted and then compared to a copy of itself. The difference between the two lines is calculated to show linearity of the system and is given as a percentage or range of least significant bits. (FiberOpticsInfo) Line Amplifier An amplifier in a transmission line that boosts the strength of a signal. (Arris Glossary of Terms) Line Extender (LE) Types of amplifiers used in the feeder system. Also known as a Distribution Amplifier. In most HFC networks configured in Node + 1 or higher integer architectures, the LE is the only transmission line amplifier connected to subscribers. 
Excerpt from ANSI/SCTE 87-1 2008, “Graphic Symbols For Cable Systems Part 1: HFC Symbols”
Photograph of Arris C-Cor Model # Flex Max 331 1-GHz LE (Courtesy of TVC Canada web site: http://www.tvccanada.com/broadband-products/broadband-amplifiers/eng/products.aspx) Line Frequency
Line Information Database (LIDB) Contains information on customers required for real-time access such as calling card personal identification numbers (PIN) for real-time validation. Line-of-Sight (LOS) Unobstructed elevation and azimuth angles necessary to properly aim a satellite antenna at a communications satellite. Also called look angle. (Arris Glossary of Terms) Line Level The level of a signal at a certain point on a transmission line, usually expressed in decibels. (Arris Glossary of Terms) Line Speed The rate at which individual bits are transmitted on a telephone connection. A modem's line speed may be set at 14,400 bits per second, an ISDN line at 64,000 bits per second. Line speed does not take into account whether the data it is sending has been compressed to increase actual throughput. Line Terminator A device used to electrically terminate the end of a coaxial line in its normal impedance for the primary purpose of minimizing ghosting. (Arris Glossary of Terms) Linear The characteristic of a device or network whose output signal voltage is directly proportional to its input signal voltage. (Arris Glossary of Terms) Linear Distortion Amplitude characteristics that are not flat over the pass band and phase characteristics that are not linear over the pass band. (Arris Glossary of Terms) Linear Transcoding A cable network operator term describing the process of receiving multi-format multimedia sources at a headend (HE), super HE, or hub, and converting them into a digital format suitable for multiplexing, transmission, and delivery to subscribers via scheduled programming. (Adams) Linear TV Scheduled television programming delivered by a broadcast network, cable operator, or other video and/or multimedia source. (Adams) Link A circuit or transmission path, including all equipment, between a sender and a receiver. (Arris Glossary of Terms) Link Encryption Cryptography applied to data as it travels on data links between the network devices. Lissajous Curves Lissajous curves are the family of curves described by the parametric equations:
Sometimes also written in the form
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