Linea de Abonado Digital-Lock Out

Linea de Abonado Digital-Lock Out

Linea de Abonado Digital

Spanish name for DSL. See DSL.

Linear Distortion

Amplitude distortion wherein the output signal envelope is not proportional to the input signal envelope. This distortion is often caused by part of the signal being bounced off something, while part arrives free and clear. Thus the receiver hears the same signal but bits of it arrive earlier and later than other bits, causing distortion. See Linearity for a better explanation.

Linear Feedback Shift Register


Linear Power Amplifier


Linear Predictive Coding

A speech coding method that analyzes a speech waveform to produce a time-varying filter as a model of the human vocal tract . See also Digital Signal Processing.

Linear Programming

Techniques in Operations Research (OR) to find an optimum solution to a linear function, given certain restrictions and typically expressed in many equations. A typical linear programming problem might be to find the least expensive, most efficient route between various pick-up and drop-off points in a transportation route.


Think of a cheap sound system. The higher you turn up the volume, the more ugly (i.e. more distorted ) your music sounds. Think of an expensive sound system. The higher you turn up the volume, the better your music sounds to you (though not to your wife). Linearity is a term for measuring the amount of distortion you get as your crank up the "volume" ” which in transmission terms ” might also be called the throughput or the bandwidth. Let's take an example we all understand: To increase their revenues , cable TV operators are offering more and more services to their customers ” including high-speed Internet access. They call these "bandwidth- intensive services." Operators are thus faced with a big problem ” how to push more information down the existing cable plant. While there are many techniques, the inevitable outcome of expanding the bandwidth (pumping more information down an existing pipe) is that a higher performance distribution system is required. That means the system has to be upgraded with better electronics, better components , better cable, etc. Increasingly, the linearity (or distortion performance) of the delivery system begins to play a critical role in the overall cost per bandwidth (how much your customer will pay) and quality of service provided to the customer. Because you lose signal power (and thus information) as your information travels down a transmission medium ( copper or glass), amplifiers are needed. But amplifiers (like those in your sound system) are the key contributor to system non-linearity (lousy sound). Amplifiers with lower distortion allow delivery costs to be reduced and system performance to be improved. Hence, there is strong demand for higher output power, ultra -linear (i.e. non-distorting) amplifiers that operate on a fixed budget of AC-line or battery power -. While it's easy to increase linearity by - consuming more power, this is usually undesirable in applications running from or being backed -up by batteries. And when more AC-line or battery power is consumed, more heat is generated, which decreases operating life expectancy. Thus you see a lot of R&D work happening in this important telecom area. In more technical language, linearity is the consistency of gain as input level is increased. If the gain response (magnitude and phase) of an amplifier changes with an increase of input level, the change indicates harmonic distortion is being generated. . In an A/D (Analog to Digital) or D/A (Digital to Analog), linearity measures the precision with which the digital output/input tracks the analog input/output.

Linearly Polarized

A mode of operation of fiber optics for which the field components in the direction of propagation are small compared to components perpendicular to that direction.


A person who fixes the telephone company's outside aerial plant ” typically the wires hanging from poles dotted across the country-side. See also Lineman's Climbers.

Lineman's Climbers

Telephone pole climbing irons which are strapped to the telephone lineman's legs, allowing him or her to climb a wooden telephone line. You can tell when a pole has been climbed by the holes left in it by the lineman's climbers.


A computer imaging term. The line tool draws straight lines, typically from point to point. Most paint packages let you continue lines in a fashion that permits rapid creation of polygons.

Lines Of Force

The directional lines of magnetic or static field which represent the stresses.

Lines Per Minute

The way of measuring the speed of a line printer. Like any measure of speed, the speed you will get from your printer may be different from what the manufacturer says. Your speed will depend on how fast you feed the printer from your computer ” a function of how fast you're transmitting, what software you're running, how fast that software can get the information to be printed off your disk, etc.

Line Side

See Lineside.


  1. Another name for a communications channel or circuit. The ATM Forum defines link as an entity that defines a topological relationship (including available transport capacity) between two nodes in different subnetworks. Multiple links may exist between a pair of subnetworks. Synonymous with logical link.

  2. A Windows command that takes several programs and subprograms that were meant to be used together, but were written separately, and combines them into one. Usually used to create an executable program out of modules that were not themselves directly executable.

  3. An element in an HTML document that points to a document or to a specific location in a document, using a URL. When the document is displayed in a browser, clicking on a link causes the browser to display the document and/or location that it points to. Links usually appear on-screen as underlined text and are usually in blue, although Web page designers can change how they look.

Link Access Protocol

A version of HDLC in which the communication line has no single controller and either of the two connected stations may initiate a data transfer operation.

Link Aggregation

The grouping of multiple network links into one logical high bandwidth link. By grouping four 100 Mbps Ethernet connections into one logical link, you can create up to 800 Mbps of bidirectional throughput between the server and the switch.

Link Aggregation Token

See Aggregation Token.

Link Attached

Describing devices that are connected to a network, a communications data link, or telecommunications circuit; compare with channel-attached.

Link Attribute

A link state parameter that is considered individually to determine whether a given link is acceptable and/or desirable for carrying a given connection.

Link Capacity Adjustment Scheme


Link Connection

An ATM term. A link connection (e.g., at the VP-level) is a connection capable of transferring information transparently across a link without adding any overhead, such as cells for purposes for monitoring. It is delineated by connection points at the boundary of the subnetwork.

Link Constraint

A restriction on the use of links for path selection for a specific connection.

Link Control Facility

A Fibre Channel hardware facility which attaches to the end of a link and manages the transmission and reception of data. The LCF is contained within each F Port (Fabric Port, i.e., switch port) and N Port (Node Port, i.e., device port). See Fibre Channel.

Link Control Protocol

LCP. A Link Control Protocol is a protocol operating at Layer 2, the Data Link Layer, of the OSI Reference Model. Such a protocol is employed by circuit terminating equipment at each end of the link in order to communicate across it. The specifics of an LCP include packet format, packet size , compression mechanisms, link performance monitoring, handshake and authentication mechanisms, and error detection and correction. LCP examples include HDLC (High-level Data Link Control) and PPP (Point-to- Point Protocol). See also HDLC and PPP.

Link Converter

A device for an InteCom S/80 which connects distributed switching modules to the centralized switching equipment through a coaxial cable or a fiber optic cable.

Link Encapsulation

LE. A function of the HiPPI Framing Protocol (FP) layer. LE encapsulates IEEE 802.2 Logical Link PDUs (Protocol Data Units) inside of HiPPI packets, thereby allowing IP traffic to travel over a HiPPI connection.

Link Layer

The logical second layer of the OSI Reference Model for Open Systems Interconnection, located between the Physical and Network layers . See OSI.

Link Layer Access Method

The algorithm that determines when any given network interface in a PC/TCP local area network is allowed to transmit. It is also known as the access method. CSMA/CD is the access method for the Ethernet.

Link Metric

An ATM term. A link parameter that requires the values of the parameter for all links along a given path to be combined to determine whether the path is acceptable and/or desirable for carrying a given connection.

Link Optimization

ISDN feature that prevents administration packet from opening the communications link and allows only user data to open the line. Link optimization ensures that remote connections are not kept open unnecessarily, which saves usage costs.

Link Protocol

The set of rules by which a logical data link is set up and by which data transfers across the link. It includes formatting of the data.

Link Pulse

A communication mechanism used in 10Base-T networks to indicate link status and, in auto-negotiation equipped devices, to communicate information about abilities and negotiate communication methods . 10Base-T uses Normal Link Pulses (NLPs) which indicate link status only. These are transmitted periodically while not transmitting packets. 10Base-T and 100Base-T nodes equipped with auto-negotiation exchange information using a Fast Link Pulse (FLP) mechanism which is compatible with NLP.

Link Rot

The process by which links on a Web page become obsolete because of changes in location or expiration of the sites to which they are connected. Link rot happens quickly.

Link Set

A group of signaling links directly connecting two signaling points.

Link State Protocol

A type of routing algorithm in which updates to routing tables are exchanged between neighboring routers only when modifications need be made. Such modifications would be required, for example, if a new link or router were added to the network, or if a link between two routers suffered a catastrophic failure. Some link state protocols provide means to assess the performance characteristics of the various available links, thereby supporting a bias toward the link performing best. Distance Vector Protocols, on the other hand, exchange routing data on a highly regular and predetermined basis, regardless of whether updates are required. Therefore, link state protocols consume less networking resources and reduce network congestion by providing updates only when needed, and sending only the changes. Periodically, the entire route table will be sent as a precautionary procedure. Examples of link state protocols include OSPF (Open Shortest Path First, ISO's IS-IS (Intermediate System-to-Intermediate System), and Novell's NLSP (NetWare Link Services Protocol). See also Distance Vector Protocol, Path Vector Routing Protocol, Policy Routing Protocol, Router, and Static Routing.

Link State Parameter

Information that captures an aspect or property of a link.

Link Status Signal Unit

LSSU. A packet sent between MTPs (Message Transfer Part of the SS7 Protocol) to provide SS7 information about the sending node and its links. This information is sent during the initial alignment of the links, when there is an associated processor outrage, or when link congestion is detected .

Link Test

A test that is performed by the hardware to ensure the integrity of the cable in a local area network. The link test can be disabled to allow old style NICs incapable of performing a link test to connect to the repeater.

Link Time

This is a specific time delay that allows access to PBX or Centrex features through a telephone system. Link Time is also referred to as a Hookswitch Flash or Recall.

Linked Object

A representation or place holder for an object that is inserted into a destination document. The object still exists in the source file and, when it is changed, the linked object is updated to reflect these changes.


  1. The transmission portion of the local loop.

  2. An affectionate name for Apple's electronic mail system, called AppleLink.


London Internet Exchange. See IX.


Linux (officially pronounced LINN-ucks) is the creation of Linus Torvalds, who started the Linux kernel as a research project at the University of Helsinki, Finland. Since then, Linux has evolved into a full-featured , powerful and robust open source, operating system based on Unix. While it is true that Linux is very closely modeled after Unix, and in most cases programs that run on Unix will run on Linux, Linux is not really Unix. Linux is among the most powerful and feature-packed operating systems available for the PC, offering a large base of hardware peripheral compatibility. Linux hosts an impressive array of compilers and development environments, including C/C++, Perl, Pascal, SmallTalk, and complete X-windows system that rivals many commercial offerings. For all its life, Linux has been free. But it is not shareware. Major parts of it are copyrighted . Linux has many script languages and parsers such as Awk, Sed, Yacc as well as all popular shells (Borne, Korn, C, BASH, etc.). The Linux kernel was originally written only for the Intel 80x86 microprocessor, i.e. the 386/486/Pentium family of chips. But it has been ported to Alphas, sparcs, 68k, and PowerPC. There are several companies selling pre-configured Alpha based systems as well as the standard 80x86 based systems. In many ways, Linux is a better performing UNIX than many of the commercial versions of UNIX. Here is the definition of Linux taken from the August, 1999 Linux Journal, the major Linux magazine. "Linux is a multi-user, multi-tasking operating system that runs on many platforms, including Intel, Motorola, MC68K, and DEC Alphas. It implements a superset of the POSIX standard. Linux works well with other operating systems, including Apple, Microsoft and Novell. It supports a wide range of software, including X Windows, Emacs, TCP/IP networking (including SLIP/PPP/ISDN), the works. A PC running Linux often makes an excellent and fast substitute for a conventional UNIX workstation. Linux (often pronounced with a short 'i' and with the first syllable stressed - LIH-nucks) is freely available ” it can be copied and redistributed without fees or royalties. The source code for Linux is available on the Internet to anyone who wants it." See, and


Lithium Ion. The Lithium Ion battery is lightweight and does not suffer from memory effect. It also delivers a higher run time average and about 80% more power per ounce. Similar to NiMH technology, LiIon batteries have a life expectancy of 500 charge and discharge cycles. LiIon batteries are typically used in mid- to high-priced portables.


Loop Initialization Protocol. Part of the FC-AL (Fibre Channel Arbitrated Loop) standard for reconfiguring the system when nodes are added or removed from the loop.


Over her lifetime, the average American woman will swallow four pounds of lipstick. The good news is that that's a lot less than the Coca Cola I drink.

Lipstick Indicator

The tendency for lipstick sales to increase prior to and during a recession .

Liquid Crystal Display

LCD. A low power display that aligns material suspended in a liquid under the influence of a low voltage so it reflects ambient light and displays alphanumeric characters . LCD displays are finding great use as methods of displaying information on new electronic telephones, especially those positioned behind PBXs. The advantage of putting such displays on telephones is that the power to drive the display is very small. The display can be line powered ” i.e. powered by the one or two pairs coming from the PBX. This avoids the necessity and cost of a transformer/ rectifier ” the little black box you plug into the wall to run your answering machine or to power up your rechargeable calculator/laptop computer. Such LCD displays on electronic phones can perform many functions. The most useful is that of "walking" the user through the phone call ” showing him/her how to transfer a call, to make a conference call, to split a conference, etc. An LCD can also alert you as to who's calling you.


Long Run Incremental Cost.


  1. Link Interface Shelf.

  2. Local Interconnection Service. A local interconnection service arrangement with an ILEC (Incumbent Local Exchange Carrier) to provide trunking, E911, SS7 requirements for LNP (Local Number Portability).


An interpretive language developed for manipulation of symbolic strings and recursive data; while the language has been developed to aid in the handling of symbolic lists, it can be and has been used successfully in the manipulation of mathematical and arithmetic logic.

List Box

A Windows term. In a dialog box, a box that lists available choices, for example, a list of all files in a directory. If all the choices do not fit in the list box, there is a scroll bar.

List Host

A host computer, in the form of a server, that is used to support e-mail list services, usually on an outsourced basis. The service provider will place your e-mail list on its host computer, and associate it with an e-mail that you want to send to many e-mail addresses. You just send the e-mail to a special target mailbox, and the list host server forwards it to everyone on your list. If people want to be removed from the list, they so indicate with a return e-mail, and the list host server takes care of it. At least that's the theory.

List Server

An automated mailing list distribution system.

Listed Directory Number

LDN. Incoming exchange network calls to the PBX via assigned listed local telephone directory number are directed to the attendant.

Listen Before Talk

LBT. Same as carrier sense multiple access (CSMA). Compare with Listen While Talk.

Listen While Talk

LWT. Same as carrier sense multiple access with collision detection (CSMA /CD). Compare with Listen Before Talk.


See Line Insulation Test.

Lit Fiber

Let's start with optical fiber. When a carrier initially installs an optical fiber in the ground (sub-terrestrial), under the ocean ( submarine ), or through the air (hung on poles), it's called "dark" fiber. That means he hasn't put any electronics on it, so he's not sending any light down the fiber and thus he's not transmitting any information. Usually a dark fiber is one of many dark fibers in a cable containing a great many fibers, commonly 432 in sub-terrestrial cabling systems. The carrier deploys such a large cabling system because the incremental cost of pulling one large cable is much less than the incremental cost of pulling fibers one at a time, as needed. The dark fibers are designated for future use, or for backup purposes in the event that a fiber fails for some reason. Sometimes dark fiber is sold or leased by a carrier without the accompanying transmission service, e.g., SONET. The customer is expected to put his own electronics and photonics on the fiber and thus be able to make transmissions. This process is calling "lighting" the fiber, since light now moves down the fiber. And the fiber is now called "lit" since that's the past participle of the verb "to light." If a given optical fiber system supports WDM (Wavelength Division Multiplexing) or DWDM (Dense WDM), multiple wavelengths of light can be transmitted across the system simultaneously . If not all of the available wavelengths are active (e.g., only 10 of a possible 32), the fiber is said to be "dim," i.e., neither dark nor fully lit. See also Dark Fiber, Dim Fiber, DWDM, SONET, and WDM.

Lithium Ion

Type of highly efficient rechargeable battery, often used in computer lap- tops and cellular portables. Here's an explanation from 1-800-BATTERIES, a seller of rechargeable batteries:

NiCad: Nickel Cadmium is the most popular and durable type of rechargeable battery. It is quick to charge, lasts about 700 charge and discharge cycles, and works well in extreme temperatures . Unfortunately, NiCads suffer from "memory effect" if they are not completely discharged during each cycle. The memory effect reduces the overall capacity and run time of the battery.

Nickel Metal Hydride (NiMH) batteries do not suffer from memory effect. Compared to a NiCad battery of equal size, NiMH batteries run for 30% longer on each charge. They are also made from non-toxic metals so they are environmentally friendly. The downside to NiMH technology is overall battery life. These batteries last for 400 charge and discharge cycles.

Lithium Ion (LiON) is the latest development in portable battery technology. These batteries do not suffer from memory effect. Compared to a NiMH of equal size, a LiON will deliver twice the run time from each charge. Unfortunately, these batteries are only available for a limited number of models and are expensive. Similar to NiMH technology, LiON batteries have a life expectancy of 400 charge and discharge cycles.

Little Endian

A format for storage or transmission of binary data in which the least significant byte (bit) comes first. See Little-endian.

Little LEO

Relatively small and inexpensive low earth orbiting satellites that provide low-cost, low-data rate, two-way digital communications, and location positioning to small handheld terminals. The frequency allocations are in the VHF band below 400 MHz. Systems include Leosat, Orbcomm, Starnet, and Vitasat. For example, the Orbcomm system requires 34 satellites for reliable full-world coverage. See Big LEO.


See Big-endian.


Line Interface Unit. Essentially a digital transceiver, an LIU is a generic term for a type of Circuit Terminating Equipment (CTE) used to terminate a T-1/E-1 circuit or ISDN PRI (Primary Rate Interface) circuit. In an optical environment, an OLIU (Optical Line Interface Unit) serves the same function for interfacing with a SONET/SDH OC-1, or better, optical circuit. Generally speaking, an LIU provides CSU (Channel Service Unit) and DSU (Digital Service Unit) functionality, supports a variety of framing formats, provides loopback test capability, and offers performance monitoring and diagnostics. The term LIU also sometimes is used to describe a PBX line card, which serves to interface PBX extensions to the switch, as opposed to trunk cards, which serve to interface the PBX switch to a CO (Central Office) switch. See also CSU, DSU, E-1, Loopback Test, SONET, SDH, and T-1.


Line Interface Unit for CCS7.

Live Bug

Colloquialism used to refer to a leaded integrated circuit package when the leads are down, like a bug that is alive and standing upright.

Live Call Screening

See LCS.


A request for an exclusive lock that is repeatedly denied because a series of overlapping shared locks in a shared database keeps interfering. A SQL server will detect the situation after several denials, and refuse further shared locks.


The human liver stretches across almost the width of the body, occupying a space about the size of a football. It weighs more than 3lbs. I have no idea why anyone other than me would be interested in this trivia.




Long Lines.


Line LoopBack. A maintenance and/or diagnostic mode of operation whereby a CSU regenerates a signal received from a span line and retransmits that signal back onto the span towards its point of origin.


Logical Link Control. A protocol developed by the IEEE 802.2 committee for data-link- level transmission control. It is the upper sublayer of the IEEE Layer 2 (OSI) protocol that complements the MAC protocol. IEEE standard 802.2 includes end-system addressing and error checking. It also provides a common access control standard and governs the assembly of data packets and their exchange between data stations independent of how the packets are transmitted on the LAN. See 802 Standards.


Logical Link Control 2. The frame format used to carry 3270 traffic on Token Ring LANs.


Local Loop Demarcation Point. See MPOE.


  1. Line Link Frame. See Crossbar Switching.

  2. Low Layer Functions.


Liar, Liar Pants On Fire, Your Nose Is Longer Than A Telephone Wire.


Low Level Wind Shear Alert System.


Long distance Marketer.


Local Multipoint Communication Service. The Canadian equivalent of LMDS (Local Multipoint Communications Service). Using frequencies above 25 GHz, LMCS produces a wireless broadband digital network capable of delivering high-bandwidth signals over the air. Industry Canada has allocated the frequency band 25.35 to 28.35 GHz for LMCS networks. Some observers believe LMCS may represent a form of fiber to the curb. See also LMDS.


Local Multipoint Distribution System. Developed by Bellcore (now called Telcordia Technologies) for Wireless Local Loop (WLL) applications, LMDS systems initially were trialed commercially in New York for point-to-multipoint broadcast TV, on the basis of an experimental FCC license granted to CellularVision. In that application, broadcast microwave signals operating at 28 GHz transmit to small receiver dishes, typically installed on the top of apartment buildings. Each of 12 transmitters in the boroughs of Manhattan, Brooklyn, Queens and portions of The Bronx covers an area of 28 square miles. At that high frequency, line-of-sight is required for maximum signal performance. This necessity for line-of-sight is the reason it wasn't installed in Manhattan (too many tall buildings ). The received LMDS signal is often then distributed through the building's central CATV system. It also can be used to broadcast directly to a subscriber's home via an 18" flat antenna sitting in the subscriber's window. There are actually all sorts of variations on the LMDS theme. In one trial, the service was used for high-speed Internet downloads to LMDS subscribers ” the Internet downloads coming from LMDS, the command to initiate those downloads being sent from the subscriber's PC over his local phone line. There is R&D going on at present to enable LMDS to carry two-way voice conversations. In Brazil, CellularVision uses LMDS technology, transmitting in the FM range, which means the signal has the ability to bounce, and to reflect off virtually any surface, thereby avoiding issues of line-of-sight and increasing the coverage area significantly. Two-way or interactive communication may be inserted between video channels for transmission back on the opposite polarity. This reverse polarization, or interweaving, theoretically allows simultaneous use of signals at the same frequency for two applications. LMDS is competitive with conventional cable-based CATV. In March 1997, the FCC set aside total LMDS bandwidth of 1.15 GHz in the 28-GHz, 30-GHz and 31-GHz frequency bands. The intent is to use LMDS for its original intended purpose of WLL (Wireless Local Loop). LMDS is competitive with conventional cable-based CATV. See also ADML, Broaband Wireless Local Loop, LMCS, MMDL, MMDS and Wireless Local Loop (WLL).


Layer Management Entity Identifier.


LMHhost is a text file which contains the NetBIOS name and IP addresses of other computers on a network. Microsoft Windows Network is a NetBIOS-based network where each computer is given a unique name, the NetBIOS name. In a traditional NetBIOS name, each machine sends a NetBIOS broadcast that announces its name as it boots. If another host already exists with that name, it will send a message to the new client saying that that name is in use. If it doesn't get a message back, the client assumes that the name is available. One of the ways to get around this broadcast problem is to create a text file named LMHost on every computer. Not a recommended course of action.


  1. Local Management Interface. A specification for the use of frame-relay products that define a method of exchanging status information between devices such as routers.

  2. Logical Modem Interface. The core of the Microsoft Fax interface. LMI lets third-party licensed vendors write plug-in modules to provide instant and transparent access to diverse underlying systems. An easy analogy for the LMI is to consider the Windows print manager. To the user, simply installing the printer driver suited to their printer is all that is required. According to Microsoft, "The LMI interface provides a similar layer between the internal fax components of Windows 95 and the fax hardware or, in our case, the fax server."


Lineup Maintenance Level.


Loop Maintenance Operations System.


A Bluetooth term. Link Manager Protocol. The LMP is used for peer-to-peer communication.

Lmp Authentication A Bluetooth term. An LMP level procedure for verifying the identity of a remote device. The procedure is based on a challenge-response mechanism using a random number, a secret key and the BD_ADDR of the non-initiating device. The secret key used can be a previously exchanged link key or an initialization key created based on a PIN (as used when pairing ).

Lmp Pairing A Bluetooth term. A LMP procedure that authenticates two devices based on a PIN and subsequently creates a common link key that can be used as a basis for a trusted relationship or a (single) secure connection. The procedure consists of the steps: creation of an initialization key (based on a random number and a PIN), lmp authentication based on the initialization key and creation of a common link key.


  1. Local Message Switch.

  2. Loop Monitoring System.


Land Mobile Satellite Service.


Line Monitor Unit.


Low Noise Amplifier.


Low Noise Block converter. The device at the focal point of the satellite dish that gathers the signal reflected by the dish to the system's low-noise block amplifier.


Low Noise Converter.


Last Number dialed .


LANE Network-to-Network Interface. An ATM term for the standardized interface protocol between LANE (LAN Emulation) servers (LES-LES, BUS-BUS, LECS-LECS and LECSLES). See also LANE and LUNI.


Local Number Portability. Similar in concept to 800/888 and other toll-free number portability, LNP was mandated by the Telecommunications Act of 1996 to level the playing field between the ILECs (Incumbent Local Exchange Carriers) and the CLECs (Competitive Local Exchange Carriers ). In July 1996, the FCC issued a ruling that LNP must be in place nationwide by January 1, 1998. Since each state is responsible for implementation of LNP, timetables vary; the specifics of the implementations vary, as well.

In some states, the implementation approach is exactly like that for 800 (toll-free) number portability. In other words, the originating central office "dips" into a centralized database of numbers via an signaling system 7 (SS7) data link. The database, known as a SCP (Service Control Point) in IN (Intelligent Network) terms, identifies the LEC (local exchange carrier) providing service to the target telephone number in order that the originating carrier can hand the call off to the terminating carrier.

In other states, such as Illinois, which is the first to implement LNP, a totally different approach is taken. This implementation involves the use of a new 10-digit telephone number, known as a LRN (Local Routing Number). When the originating CO switch consults the SCP, the new 10-digit number is provided along with the identification of the CLEC to which the service has been ported. The originating carrier then hands off the call to the CLEC. While this approach is claimed to be faster, clearly two telephone numbers are required, thereby placing additional pressure on the North American Numbering Plan (NANP).

To implement LNP, the FCC has mandated a system of regional databases, which will store master copies of all porting information. These databases will be maintained by regional Number Portability Administration Centers (NPACs) that will serve as number portability clearinghouses for all local operators. Originally, the deal was that Lockheed Martin would maintain the databases in four regions and Perot Systems in three regions . After Perot had some problems getting going on time, Lockheed Martin was selected to run all seven. That responsibility now rests with NeuStar, which was an independent business unit within Lockheed Martin before being spun off.

In either case, LNP will require the SCPs be established by LECs, CLECs, IXCs (inter- exchange carriers) and wireless carriers. Further, the SCPs must be synchronized in order that the databases are consistent across them all. The concept is simple, but its implementation is complex and expensive. MNP (Mobile Number Portability) is the LNP version intended for eventual use in certain mobile networks. See also Number Portability and Trigger.


Local Number Portability Administration. See also LNP and NANC.


Like New Repair and Update. A term in the industry which repairs telecom equipment. It means all equipment is repaired and updated to the current manufacturer's specifications. New plastic is used to refurbish to a "like new" status. Also added are a new coil cord, line cord and address tray. Included is a full diagnostic test with a burn-in (if required) and an operational system test. Definition courtesy Nitsuko America. See also Repair And Quick Clean and Repair, Update And Refurbish.


Local Operator. In the PCS sense, a functional entity providing local wireless service to customers in a geographical region. The LO (Local Operator) is serviced by the National Services Organization in the PCN (Personal Communications Network) for long-distance communications and for marketing/sales.


Letter Of Agency. A letter that you give to someone whom you allow to represent you and act on your behalf. For example, a letter of agency is used when your interconnect company orders lines from your local phone company on your behalf . Letters of Agency are also used when companies switch their long distance service from one carrier to another. A blanket LOA can mean everything from a group of numbers belonging to one customer at multiple sites or multiple customers at multiple sites.


  1. The act of taking a program or data from external storage ” a cassette, a floppy or hard disk, etc. and storing it in the computer's main RAM memory.

  2. The load is any electric or electronic appliance or gadget plugged into an AC electrical outlet. It completes the circuit from the transformer through the hot conductor, to the load, through the neutral conductor and back to the utility transformer. See AC, AC Power, Ground and Grounding.

Load Balance

A telephone company term. Load Balance is the even distribution of customer traffic volume across all loading units in a switching entity. Load Balance is not related to the absolute level of load, but only to how well the existing load is distributed. See also Load Balancing.

Load Balance Index

LBI. A telephone company term. Indicates trends, identifies superior performances and points up opportunities for improvement in load balance administration of dial Central Office line equipment.

Load Balancer

In server farms, a load balancer accepts IP packets and then distributes them among identical web servers. This enables the manager to add web servers as loads grow, or to take a server out of service and not have the clients notice. This definition contributed by Alan Simmons. See also Load Balancing.

Load Balancing

The practice of splitting communication into two (or more) routes. By balancing the traffic on each route, communication is made faster and more reliable. In telephone systems, you can change phone and trunk terminations in order to even out traffic on the network. An example: You have a PBX of three separate cabinets, each of which are joined by tie lines. Instead of having each cabinet serve anyone in the building, you might figure which groups talk to each other the most and concentrate them into specific cabinets. The objective is to maximize the number of calls that can be handled inside each cabinet and reduce the number of calls that need to travel between the cabinets . This makes the calls go faster and reduces the need for inter- cabinet lines.

In data internetworking, bridges and routers perform load balancing by splitting LAN-to- LAN traffic among two or more WAN links. This allows for the combination of several lower speed lines to transmit higher speed LAN data simultaneously. In local area networking, load balancing is a function performed by token ring routers. In data networking, load balancing can also be a form of inverse multiplexing where data packets are alternated over all available circuits. At the receiving end, the packets are reassembled in their proper order.

In disk arrays, load balancing means using multiple power supplies within a disk array so that power usage is spread equally across all the power supplies . The failure of one supply will not cause the entire array to fail. See also Load Balancer.

Load Coil

Load coils are also known as impedance matching transformers . Load coils are used by the telephone companies on long analog POTS (Plain Old Telephone Service) lines to filter out frequencies above 4 kHz, using the energy of the higher frequency elements of the signal to improve the quality of the lower frequencies in the 4 kHz voice range. Load coils are great for analog voice grade local loops, but must be removed for digital circuits to function. Load coils must be removed for DSL loops , as the frequencies required are well above 4 kHz.

Load Coil Detector

A device use to detect unseen load coils on a wire pair. See Load Coil.

Load Factor

Ratio of the Peak to Average ratio over a designated time period; has meaning in both traffic engineering and in transmission technology, particularly for data transmission.

Load Leveling

Load can apply to telecommunications traffic or electricity (AC or DC). Load leveling in telecom typically means distributing traffic over more than one route. Load leveling in electricity typically means

Load Number

Load number is the Canadian equivalent of the U.S. concept of Ringer Equivalence. The idea is that each phone or "phone thing" you buy (e.g. answering machine) comes with a number. You add the numbers together and if you get above a certain number, you are drawing too much current and none of the bells on the phones will ring. In Canada, single line phones are typically rated at 10 for the newer ones with electronic "bells" or 20 for the older electro-mechanical ones with real metal bells. In Canada, the rule is not more than 100 points on a line. In the U.S., phones are typically one and the rule is not more than five points on a line.

Load Service Curves

The output from load and stress testing on a computer telephony system is a set of load service curves. Load service curves identify how individual areas of the system respond under various load amounts. Traffic is provided to the computer telephony system at defined steps (perhaps at 1,000 call per hour increments ) until the system design threshold is reached. Measurements are taken at each step, and usually shown graphically, in a "curve". Most computer telephony systems are designed to handle up to a specified number of busy hour calls with specific response times. For example, the time that passes between the point in time a caller enters a DTMF digit and the point the computer telephony system speaks a response should usually be no more than 1 second 97% of the time, nor more than 3 seconds 99% of the time. A load service curve would be used to illustrate the response time at each step of increasing load. When the load curve shows the response time is slower than the above parameters, the system has reached its capacity. Of course, the load placed on the system must accurately mimic the real world load the system will experience or it is largely meaningless. This definition from Steve Gladstone, president, Hammer Technologies, makers of fine computer telephony testing systems, 508-694-9959.

Load Sharing

In data processing, load sharing is the technique of using two computers to balance the processing normally assigned to one of them. In local area networking, load sharing is performed by token ring routers when connecting remote LANs. It allows combining Ethernet and Token Ring traffic over a common WAN (Wide Area Network) link such as T-1 or 56 Kbps circuit. Loads sharing eliminates the need for duplicate WAN links (and bridges or routers) each serving a different type of LAN.

Load Testing

Also known as stress testing, the goal of load testing is to make sure the system will meet or exceed its busy hour load capacity objectives under all operating conditions. This requires stressing the system in incremental steps until it breaks and understanding what happens when the system is operating under its full rated transaction load? Beyond its load? Does it slow down? How? Does it fail? Where? How is service restored after an outage ? Is service restoration graceful or must the system reboot? Is restart manual or will the system reset itself? Individual load tests may be performed to understand the impact of load on specific system bottlenecks. Most significant architectural problems will come to light under load testing. It is critical that any load placed on a computer telephony system be dynamic, and mimic the load characteristics the system will experience under real-world usage and conditions. See also Dynamic Load Testing and Load Service Curves.

Loaded Cable

Twisted wire pair into which inductors have been inserted at periodic intervals to approximate the optimum ratios of the primary cable constants for minimum loss. A loaded cable acts like a lowpass filter. Transmission loss below the cutoff frequency is reduced below that for the nonleaded cable and is nearly flat. Above the cutoff frequency, loss increases very rapidly . See Loading.

Loaded Line

A telephone line equipped with loading coils to add inductance in order to minimize amplitude distortion. See Loading and Loading Coil.

Loaded Loop

Also called a Loaded Pair (loaded twisted pair); a loop that contains series inductors, typically spaced every 6000 feet for the purpose of improving the voice- band performance of long loops. However, high bandwidth DSL operation over loaded loops is not possible because of excessive loss at higher frequencies. See Loading.


A method of improving the voice quality of a phone line. Telephone companies put load coils on local lines. What this loading does is to insert inductance in a local loop circuit to offset the effect of capacitance in the cable. Loading "tunes" the circuit to the voice frequency band (500 to 2500 Hz) and thus improves the quality at the expense of overall bandwidth. You usually have to ask that the loading coils be removed if you're planning to transmit high-speed data exclusively on that circuit. See Loading Coil.

Loading Coil

See Load Coil.

Loading Division

A telephone company term. A group of the same type of equipment designed to be loaded similarly by both usage and classes of service.

Loading High

A memory management verb for loading a device driver or TSR (Terminate and Stay Resident) program into upper memory, out of conventional memory. Under DOS, the loading high commands are DEVICEHIGH for device drivers and LOADHIGH (or LH) for TSRs. Third party memory managers use their own routines to load high, though they can sometimes borrow DOS commands.

Loading Plan

A telephone company term. A Loading Plan is a systematic scheme for fully utilizing all existing capacity in a given switching entity; Utilizing and coordinating the capabilities and capacity limitations of various entities in a multi-entity wire center and maintaining objective service levels at all times. A Loading Plan is the basis for achieving and retaining good Load Balance.


An ATM term. Loss of Cell Delineation: A condition at the receiver or a maintenance signal transmitted in the PHY overhead indicating that the receiving equipment has lost cell delineation. Used to monitor the performance of the PHY layer.


Pertaining to a system or device that resides within a subject device's switching domain.

Local Access

The connection between a customer's premises and a point of presence of the Exchange Carrier.

Local Access and Transport Area

LATA. The MFJ (Modified Final Judgement), which broke up the Bell System, also defined 196 distinct geographical areas known as LATAs. The LATA boundaries generally were drawn in consideration of SMSAs (Standard Metropolitan Statistical Areas), which were defined by the Census Bureau to identify "communities of interest" in economic terms. Generally speaking, the LATA boundaries also were coterminous with state lines and existing area code boundaries, and generally included the territory served by only a single RBOC. The basic purpose of the LATA concept was to delineate the serving areas reserved for LEC (Local Exchange Carrier) activity. In other words, IntraLATA traffic (i.e., local and local long distance) became the sole right and responsibility of the LECs. InterLATA traffic, on the other hand, became the sole right and responsibility of the IXCs. Over time, a number of state PUCs allowed the IXCs to compete for IntraLATA long distance; they also allowed CAPs (Competitive Access Providers) to provided limited local service in competition with the LECs. The Telecommunications Act of 1996 (The Act) opened the floodgates for competition with the LATA boundaries. The Act also allows the RBOCs to provide InterLATA service outside the states in which they provide local service. Additionally, The Act contains provisions for the RBOCs to offer InterLATA service within the state in which they provide local service, once they have satisfied a 14-point checklist, the most significant conditions of which relate to significant, demonstrated levels of competition within their respective local exchange serving areas. California is divided into 11 LATAs. Sparsely populated states such as South Dakota comprise only a single LATA.

Local Airtime Detail

This cellular telephone carrier option (which means it costs money) provides a line-itemized, detailed billing of all calls, including call attempts and incoming calls to the mobile. What you get for free is generally a non-detailed, total summary of all calls.

Local Area And Transport Area


Local Area Data Transport

LADT. A service of your local phone company which provides you, the user, with synchronous data communications.

Local Area Network

LAN. A short distance data communications network (typically within a building or campus) used to link computers and peripheral devices (such as printers, CD-ROMs, modems) under some form of standard control. Older data communications networks used dumb terminals (devices with no computing power) to talk to distant computers. But the economics of computing changed with the invention of the personal computer which had "intelligence" and which was cheap. LANs were invented as an afterthought ” after PCs ” and were originally designed to let cheap PCs share peripherals ” like laser printers ” which were too expensive to dedicate to individual PCs. And as time went on, what LANs were used for got broader and broader. Today, LANs have four main advantages:

  1. Anyone on the LAN can use any of the peripheral devices connected to the LAN.

  2. Anyone on the LAN can access databases and programs running on client servers (super powerful PCs) attached to the LAN; and

  3. Anyone on the LAN can send messages to and work jointly with others on the LAN.

  4. While a LAN does not use common carrier circuits, it may have gateways and/or bridges to public telecommunications networks. See LAN Manager, Token Ring and Ethernet.

Local Area Signaling Services

LASS is a group of central office features provided now by virtually all central office switch makers that uses existing customer lines to provide some extra features to the end user (typically a business user). They are based on delivery of calling party number via the local signaling network. LASS can be implemented on a standalone single central office basis for intra office calls or on a multiple central office grouping in a LATA (what the local phone companies are allowed to serve) for interoffice calls. Local CCS7 (Common Channel Signaling Seven) is required for all configurations. The following features typically make up LASS:

Automatic Callback: Lets the customer automatically call the last incoming call directory number associated with the customer's phone when both phones become idle. This feature gives the customer the ability to camp-on to a line.

Automatic Recall: Lets the customer automatically call the last outgoing call currently associated with the customer's station when both stations become idle. This feature gives the customer the ability to camp-on to a line.

Customer-Originated Trace: Lets the terminating party request an automatic trace of the last call received. The trace includes the calling line directory number and time and date of the call. This information is transmitted via an AM IOP channel to a designated agency, such as the telephone company or law enforcement agency.

Individual Calling Line Identification: Consists of two distinct features: 1. Calling Number Delivery which transmits data on an incoming call to the terminating phone. 1. Directory Number Privacy which prevents delivery of the directory number to the terminating phone.

Also, LASS has some selective features:

Selective Call Acceptance: Allows users to restrict which incoming voice calls can terminate, based on the identity attribute of the calling party. Only calls from parties identified on a screening lists are allowed to terminate. Calls from parties not specified on a screening list are rerouted to an appropriate announcement or forwarded to an alternate directory number.

Selective Call Forwarding: Allows a customer to pre-select which calls are forwarded based on the identity attribute of the calling party.

Selective Call Rejection: Allows a customer to reject incoming voice calls from identity attributes which are on the customer's rejection list. Call attempts from parties specified on the rejection list are prevented from terminating to the customer and are routed to an announcement which informs the caller that his/her call is not presently being accepted by the called party.

Selective Distinctive Alert: Allows a customer to pre-select which voice calls are to be provided distinctive alerting treatment based on the identify attributes of the calling party.

Users can, at their convenience, activate or modify any of these features by sending commands to the central switch from their existing touchtone telephones.

Local Attack

A network security term. An attack that targets the machine on which the attacker is interactively logged on.

Local Automatic Message Accounting

LAMA. A combination of automatic message accounting equipment and automatic number identification equipment in your telephone company's central office and used by them to bill your local phone calls.

Local Battery

Having "local battery" means the telecom equipment ” the telephone, the PBX, the key system, etc. ” has its own source of power and does not draw from the power coming down the phone line. The term came from telegraphy and was used to distinguish the battery which provided power to the telegraphic station as against the power that went to drive the line and the signal traveling down it. See Battery.

Local Bridge

A bridge between two or more similar networks on a local site (within same building).

Local Bus

A microprocessor inside a PC must communicate with certain integral devices, including memory, video controllers, hard disks. This is typically called an internal bus. That is to distinguish it from the "external" bus, such as the AT, ISA, EISA, MCA buses, which define the communications between the motherboard and the various peripheral devices, such as the I/O cards like those handling modems and LAN connections. As microprocessors have gotten faster, so they have begun to outpace the speed of their computer's internal bus, which has tended to narrow the stream of data in and out of the CPU, slowing the computer. A Local Bus is a new type of internal bus. It is a faster bus. The idea is to get a broader path between your critical components ” memory, video and disk controller ” and your microprocessor. The idea is to get the data in and out of the microprocessor at the same speed as the microprocessor's system clock. Local Bus is an emerging standard. See also EISA, PCI and VESA.

Local Call

Any call within the local service area of the calling phone. Individual local calls may or may not cost money. In many parts of the US, the phone company bills its local service as a "flat" monthly fee. This means you can make as many local calls per month as you wish and not pay extra. Increasingly this luxury is dying and local calls are costing money.

Local Call Accounting

Computes the dollar amount for local calls based on the total message units stored for each phone.

Local Call Billing

Computes the dollar amount for local calls placed by guests based on total message units.

Local Central Office

Switching office in which a subscriber's lines terminate.

Local Channel Controller

An AT&T name for its family of 3270 compatible cluster controllers.

Local Composite Loopback

In network management systems. Composite loopback test that forms the loop at the output of the local multiplexer that returns transmitted signals to their source. See loopback.

Local Dataset

Signal converter that conditions the digital signal transmitted by an RS-232 interface to ensure reliable transmission over a dc continuous metallic circuit without interfering with adjacent pairs in the same telephone cable. Normally conforms with Bell 43401. Also called baseband modem, limited distance modem, local modem, or short- haul modem. See line driver.

Local Digital Services

LDS. LDS is a term used by long distance companies to describe "last mile" services provided by local phone companies. LDS is generic word to describe any digital services, including T-1, T-3, OC-12, Frame Relay and dedicated Internet services.

Local Distribution Frame

LDF. Another word for an Intermediate Distribution Frame. It's a device for cross connecting cables ” from one thing to another. On one side of the LDF are the pairs from individual phones in that part of the building or area. On the other side are trunks coming in from a central office or cables coming in from the central, larger PBX. LDFs typically help with the organization of cables in a building or area. See also Intermediate Distribution Frame.

Local Echo

A modem feature that enables the modem to send copies of keyboard commands and transmitted data to the screen. When the modem is in Command mode (not online to another system) the local echo is invoked through the ATE1 command. The command causes the modem to display your typed commands. When the modem is online to another system, the local echo is invoked through the ATFO command. This command causes the modem to display the data it transmits to the remote system.

Local Exchange

The telephone company exchange where subscribers lines are terminated . Also called an "End Office."

Local Exchange Carrier

A local phone company. See also LEC. As defined by the Telecommunications Act of 1996, a local exchange carrier means any person that is engaged in the provision of telephone exchange service or exchange access. Such term does not include a person insofar as such person is engaged in the provision of a commercial mobile service under section 332(c), except to the extent that the Commission (the Federal Communications Commission) finds that such service should be included in the definition of such term.

Local Explorer Packet

Packet generated by an end system in an SRB network to find a host connected to the local ring. If the local explorer packet fails to find a local host, the end system produces either a spanning explorer packet or an all-routes explorer packet.

Local Heap

A memory storage area limited to 64K in size.

Local IP

A telephone company AIN term. The Internet Protocol (IP) indicated when an SCP or Adjunct requests a local AIN switch to make a connection to an IP to which the SSP or ASC switch has a direct ISDN connection.

Local Long Distance

IntraLATA long distance. A marketing term invented by the LECs (local exchange carriers) to distinguish intraLATA from interLATA toll calling. Specifically, the term was invented by the RHCs (Regional Holding Companies), which currently are limited to providing "long distance" calls only within the intraLATA toll market in their home states.

Local Loop

The physical connection from the subscriber's premise to the carrier's POP (Point of Presence). The local loop can be provided over any suitable transmission medium, including twisted pair, fiber optic, coax, or microwave. Traditionally and most commonly, the local loop comprises twisted pair or pairs between the telephone set, PBX or key telephone system, and the LEC (Local Exchange Carrier) CO (Central Office). As a result of the deregulation of inside wire and cable in the United States, the local loop typically goes from the demarc (demarcation point) in the phone room closet, in the basement or garage, or on the outside of the house, to the CO. The subscriber or building owner is responsible for extending the connection from the demarc to the phone, PBX, key system, router, or other CPE device. See also Demarc and Subloop.

Local Management Interface

LMI. The specification for a polling protocol for use in Frame Relay networks between the user equipment in the form of a FRAD (Frame Relay Access Device) and the network equipment in the form of a FRND (Frame Relay Network Device). The LMI verifies the existence of the UNI (User Network Interface) and the Permanent Virtual Circuit (PVC).

Local Measured Service

LMS. Years ago virtually all phone lines in the United States were FLAT RATE. That meant that for a fixed amount of money each month, you, the customer (a.k.a. subscriber) were allowed to make as many local calls as you wanted. For many reasons, the U.S. phone industry has progressively moved to LOCAL MEASURED SERVICE for local calls. Typically this means that for a fixed amount of money each month, you, the customer, can receive as many calls as you want and can make a finite number of outgoing local calls ” typically 50. Each additional call beyond the 50 (or whatever the number is) costs extra. How much that call costs depends on the distant the call travels, the time of day, the day of the week, and the local company's tariffs.

Local Multipoint Communications Service


Local Multipoint Distribution System


Local Net

The broadband architecture used in Sytek's work. Also the product name of their network. Sytek is in Sunnyvale, CA.

Local Number Portability

LNP. Imagine a town in which there are many local phone companies. You have service from one company. But another comes along offering better service, lower price and more features. You want to switch. But you don't want to change your phone number. That's what LNP is all about ” the ability to change your phone company and still keep your phone number.

Regardless of the local provider selected, consumers will continue to have access to Emergency 911 service; operator and directory assistance services; advanced services such as voice mail, Caller ID and Call Forwarding; and other customized local area and signaling capabilities, including equal access to all 800 and 888 toll-free telephone numbers.

On November 15, 1997 I received a press release from Lockheed Martin saying that they had successfully developed and tested Local Number Portability (LNP) in the Midwest, the FCC's mandated national test region. The implementation was mandated by the Federal government as part of the Telecommunications Act of 1996, which required this process be completed by October, 1997. In the press release, Lockheed Martin explain that in 1994, amidst concern over the need for fair, open telecommunications markets, the MCI Telecommunications Corporation initiated a Gallup Poll to investigate the demand for a Local Number Portability system. The poll randomly surveyed approximately 2000 businesses and consumers across the country in September and October 1994. The study assessed whether business or consumers would switch local telephone service providers under various market scenarios. The results of the poll indicated that 83 percent of business customers and 80 percent of residential customers would not change local service providers if changing service providers meant changing phone numbers. The study helped articulate the need for LNP in order to facilitate fair and open market competition in the local telecommunications industry. The LNP system developed in response to that survey and completed by Lockheed Martin in October, 1997, represents a substantial benefit to consumers: They now can choose local service from a variety of providers without changing their phone numbers. The system works for voice, data, and video lines, residential and business lines.

Here is what Lockheed wrote about local number portability technology in that press release: The database that facilitates Local Number Portability is a technological marvel in its complexity and the speed with which it operates. Each phone number has a network address. The LNP database keeps track of these addresses. When a customer places a call, the database records the caller's network address, locates the dialed number's network address, and notifies all telecommunications companies involved where to route the call and which companies to credit for the call.

Simplified, the process works like this:

  • Call placed

  • Network address of caller identified

  • Network address of call recipient identified

  • Telecommunications companies told how to route the call and which companies to credit.

All of this happens within nano-seconds of the customer placing the call ” an imperceptible lapse of time. The LNP system also records the appropriate information whenever a customer changes local carriers, updating account information and ensuring that no interruption in service occurs.

In developing LNP, Lockheed Martin IMS drew on two types of existing technology. In 1993, Lockheed Martin IMS developed a portability system for 800 numbers that was used by 140 telecommunications companies in the United States at the request of Bellcore, the research and engineering division of the Regional Bell Operating Companies. This database allowed customers to handpick 800 numbers (such as 1-800-FLOWERS) and keep those numbers regardless of the long-distance carrier used. That experience laid the groundwork for developing LNP.

Lockheed Martin IMS also used existing infrastructure to run LNP. Twenty years ago, each local phone company installed computerized databases for their own internal use. LNP is an incremental application of this network, the Advanced Intelligent Network (AIN), and was made possible by the investment that local service providers made years ago. See also LNP and Location Portability.

Local Order Wire

A communications circuit between a technical control center and selected terminal or repeater locations.

Local Oscillator

LO. A device which generates a specific single wave frequency. A local oscillators is used to reduce a high microwave frequency to a low intermediate frequency, so that it can be processed .

Local Phone

A phone attached to your computer. See also Handset Management.

Local Phone Service

When I dial the pizza store on the corner, I'm making a local phone call. But when I'm calling the pizza store 50 blocks away, is that a local phone call? Answer, it could be. It depends. What's local phone service? What do you charge for it? Once upon a time, most Americans didn't pay for local phone service. They paid a flat monthly fee. Then the phone companies needed money, so they started charging for local service. A few cents per call. Then the phone companies timed the call and charged more the longer you talked. Then they started charging for longer local calls ” maybe for calls of ten miles and further. In short, the definition and pricing of local phone calls is changing. Now local calls are looking increasingly like long distance calls ” charged by time, distance, and day of the week.

Local Printer

A printer that is directly connected to one of the ports on your computer.

Local Redirector

A local redirector is a shim that redirects HTTP requests to a local proxy server. A local redirector is also known as a load balancer, a local redirector is a piece of software that receives a server request (e.g., HTTP, FTP or NFS) and reroutes it to one of a cluster of Web servers to be actioned. The distribution function may be based on which machine in the cluster has the lowest current level of utilization, the proximity of the server to the client, or which machine has the resources necessary to carry out the request. This definition courtesy of Mark Gibbs.

Local Service Area

The geographic area that telephones may call without incurring toll charges. A flat rate calling area. Increasingly rare.

Local Service Management System


Local Service Ordering Guidelines

LSOG. A manual that describes and provides examples of the LSR (Local Service Request) forms that are used by a CLEC to communicate with an ILEC for the purpose of ordering changes, additions, deletions, or enhancements in service. For example, LSRs are used to order various types of local loops, to port telephone numbers. The LSOG is printed and distributed by Telcordia Technologies (nee Bellcore) under the auspices of the Ordering and Billing Forum (OBF) of the Carrier Liaison Committee of the Alliance for Telecommunications Industry Solutions (ATIS). See also ATIS, CLEC, ILEC, LSR, OBF, and Telcordia Technologies.

Local Service Request

A form used by a CLEC (Competitive Local Exchange Carrier) to request local service from an ILEC (Incumbent LEC). See LSR for a full explanation.

Local Switch

The term local switch refers to the switch (PBX, ACD, dumb) to which the computer telephony system is directly connected. Usually, the local switch will provide better integration with the computer telephony system (more comprehensive call data) than connections that take place over the network. Additionally, the local switch will have both line and trunk side connections and will also support connection to whatever agents or desktop users that may use the computer telephony application.

Local Switching Center

The switching center where telephone exchange service customer station channels are terminated for purposes of interconnection to each other and to interoffice trunks.

Local Tandem

A central office, usually in large metropolitan areas, serving as a transit switch between noncontiguous class 5 exchanges. It connects end office trunks.

Local Test Desk

A testing system that is used to test local loops and central office subscriber line equipment from a central point, typically a central office.

Local Traffic

Telephone calling traffic that is classified as "local" in the tariff on file with the appropriate state regulatory body. This term includes single and multimessage unit traffic. See Toll Traffic.

Local Trunk

Trunks between Class 5 local central offices, also called switching centers.


Local Device. A Bluetooth device which initiates a SDP procedure. A Local Device is typically a master device on the piconet. However, a Local Device may not always have a master connection relationship to other devices. See also RemDev.


A measure of how close commonly-accessed files are to one another on a hard disk. "High locality" means the files reside on sectors or tracks which are close to each other. When this is the case, seek times during operation are shorter than average.


Apple Computer's proprietary Local Area Network (LAN) for linking Macintosh computers and peripherals, especially LaserWriter printers is called Appletalk. AppleShare is the company's networking software, and the LAN hardware is called LocalTalk. Appletalk is a CSMA/CA network that runs at 230.4 Kbps and is therefore incompatible with any other LAN. It is also a lot slower than the present top speeds of Ethernet (100 Mbps) and Token Ring (16 Mbps). Outside manufacturers, however, make gateways which will connect an Appletalk LAN to other local area and telecommunications networks ” LANs, WANs and MANs. See also AppleTalk, Ethernet, and CSMA/CA.


One definition is the place where a telephone jack is located. This location is given a number. The wire going to that location is given a number. All this in hope of being organized for installation, moves, changes and maintenance.

Location Based Services

Location based services enable personalised (customised) services to be offered based on a person's (item's) location. Services include areas of security, fleet and resource management, location based information, vehicle tracking, person-to-person location and messaging applications. To enable these services, there are a number of different technology layers that need to be co-ordinated on a network. These technologies include Applications, Middleware, Determination technologies and associated Silicon and Intellectual Property (IP). See Location Services.

Location ID

A feature of the IS-136 standards for digital cellular networks employing TDMA (Time Division Multiple Access). A capable telephone set will display the name of the cellular carrier providing service. In a wireless office system application, the phone can display the name of the company. When you are at home, connected to your PBS (Personal Base Station), the phone can display "cordless."

Location Interoperability Forum

LIF. Open standards forum announced in September of 2000 to develop and promote a simple, ubiquitous interoperable location service solution necessary for mass consumer acceptance of mobile location services. Motorola, Nokia, and Ericsson were the charter members . See also LIF and Location Services.

Location Portability

The ability of an end user to retain the same geographic or non-geographic telephone number (NANP numbers) as he/she moves from one permanent physical location to another. Location Portability will involve either of the following scenarios: 1) new location is within the same central office area, or 2) new location is within a different central office area. See also Local Number Portability.

Location Services

Cellphone carriers will soon be able to figure out, within 100 metres (or less), where you, a cellphone user, are. The first application of this technology is called Emergency Location Services (or E911). What this means is that if you dial 911 in the United States on your cellphone, the operator will know where you are and be able to send help. There are two technologies currently being adopted; E-OTD (Enhanced Observed Time Difference) uses a software-enabled cellphone handset and cell sites to calculate your location. GPS (Global Positioning Systems) relies on a chip being installed in the cellular phone and orbiting satellites to determine position. From October 1, 2001, the FCC mandated 50% of all the new cellphone activations in the United States should be equipped with location services. See E-OTD, GPS and Location Based Services.

Location Tracking

Vehicle Location Tracking Devices (VLD) are products targeted at the mobile fleet/ vehicle management space. Weighing less than eight ounces, they can be installed in almost any vehicle including: automobiles; construction equipment; trucks ; buses; motorcycles or even boats. When used with a carrier-grade server, it allows users to track the locations of specific vehicles equipped with these devices, via the Internet. I first heard about this from a company called Paradigm Advanced Technologies, Inc., which provides wireless location-based electronic commerce (L-Commerce) solutions. Paradigm has licensing rights to a wireless location patent (US Patent #B1 5,043,736) covering the apparatus and method of transmitting position information from satellite navigational signals (like GPS) over cellular systems to a base unit, and displaying the location of a person or object so equipped. Paradigm owns PowerLOC Technologies Inc. , which anticipates providing a comprehensive range of L-Commerce and L-Business products and services including a family of proprietary wireless-location devices for this industry and for location- based service providers (LSPs) in particular.

Location Transparency

More professionals are working from home, customer sites or from the road. Location transparency means that your communications system ” faxing, email, voice mail, etc ” works as well for you, the user, whether you're in the office or in the field, or where in the field you are.


A term used in the secondary telecom equipment business. A locator is a company that assists both a buyer and seller to quickly find each other. A locator contracts with dealers to provide them with daily lists of potential customers. The list develops from phone calls to an 800-number asking for a specific component.

Lock And Load

Originally a military term. Then it became software speak for freezing code on a program in development. Then it became "Let's make a decision and get on with it."

Lock Code

The lock code locks a cellular telephone to prevent unauthorized use. The lock code is programmed into the NAM (Numerical Assignment Module) and is frequently factory set to either 1234 or 00004.

Lock On

The process by which an earth station initially acquires the signal from a satellite.

Lock Out

In a satellite telephone circuit controlled by an echo suppressor , one or both subscribers can't get through because of excessive noise at one end. You get this also with speakerphones. The person with the speakerphone can simply hog the conversation because his speakerphone keeps transmitting his voice. There are weird variations on this. Sometimes you might call someone on your speakerphone and wait for them to pick up. They do. They shout into the phone "I'm here." All they can hear is you at the other end talking or typing. The sound at your end is hogging the channel and thus locking out the person at the other end. The solution? Turn the "mute" button on your speakerphone. This will stop your end transmitting and allow the other end to say "Hello, I'm here." See also Lockout.

Newton[ap]s Telecom Dictionary
Newton[ap]s Telecom Dictionary
ISBN: 979387345
Year: 2004
Pages: 133 © 2008-2017.
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