A & B Bit is used in digital environments to convey signaling information. A bit equal to one generally corresponds to loop current flowing in an analog environment; A bit value of zero corresponds to no loop Current, i.e. to no connection. Other signals are made by changing bit values: for example, a flash-hook is sent by briefly setting the A bit to zero.
A Links, also known as SS7 access links, connect an end office or signal point to a mated pair of signal transfer points. They may also connect signal transfer points and signal control points at the regional level with the A-links assigned in a quad arrangement.
A&B Bit Signaling, also called 24th channel signaling, is a procedure used in T1 transmission facilities in which each of the 24Â T1 subchannels devotes 1 bit of every sixth frame to the carrying of supervisory signaling information. On T1 lines that use Extended SuperFrame(ESF) framing, the signaling bits are robbed from the 6th, 12th, 18th, and 24th frame, resulting in "ABCD" signaling bits.
ABAM cable refers to a type of T1 cable. This cable was a 22 gauge, 100 ohm insulated, twisted pair. ABAM cable is no longer available, but you can easily find cable that meets the technical requirements.
Abandoned Call is a call in which the call originator disconnects or cancels the call after a connection has been made, but before the call is established.
Abandonment refers to the network replacement of a connect signal with an on-hook signal (network) prior to receiving a CI (customer installation) answer signal. Abandonment is the only way to end an unanswered call attempt.
Abbreviated Address is an address that has fewer characters than the full address, usually for special communications and other services or for certain users. Examples of abbreviated addresses are (A) a four-digit telephone number for a user calling another user connected to the same switching exchange, and (B) message addresses that have only the addressee name and station code or number.
Abbreviated Address Calling is a calling that enables a user to employ an address having fewer characters than the full address when initiating a call. Communications network users may be allowed to designate a given number of abbreviated address codes. The allocation of the abbreviated address codes to a destination or group of destinations may be changed as required, by means of a suitable procedure.
Abbreviated Dialing is a telephone feature (synonym speed dialing ) that (A) permits the user to dial fewer digits to access a network than are required under the nominal numbering plan, and (B) is limited to a subscriber-selected set of frequently dialed numbers.
ABCD signaling is a 4-bit telephony line signaling coding in which each letter represents 1 of the 4 bits. This often is associated with CAS or robbed-bit signaling on a T1 or E1 telephony trunk.
ABCD Signaling Bits, also refered as ABCD Bits, are 4-bits telephony line signaling coding in which each letter represents 1 of the 4 bits. The implementations of ABCD signaling are different in E1 and T1 digital trunks. On E1, ABCD bit values may be used to signal an incoming call, disconnect, seize and so on, They are closely analogous to the A and Bits commonly used on T-1 digital trunks. On E1, there are 32 channels (time-slots) in contrast to 24 channels on T-1, hence the faster bit rate of 2.048 MHz versus 1.544 MHz for T-1. On E1, channels 0 and 16 are used to carry the ABCD bits and synchronization (framing) bits; hence only 30 channels are available for audio conversations. On T-1 digital trunks, the ABCD Signaling Bits implements the robbed bit signaling.
ABCD Tones are simply additional DTMF tones that may be used in any way the standard (0-9) tones are used. The ABCD Tones are used in the U.S. Military telephone network (Aoto Von), in some Automatic Call Distributor (ACD) systems, for control messages in some PBX systems, and in some amateur radio auto-patches.
ABDN: Attendant Blocking of Directory Number
Attendant Blocking of Directory Number (ABDN) is a feature of telephone service enables the attendant to block a DN (Directory Number) for a telephone from receiving to making calls. This is particularly useful when a caller dials the attendant DN and requests an external (long distance) call. If the caller chooses to disconnect until the attendant successfully places the call, the requesting DN becomes idle and can receive or make calls. Therefore, the requesting DN could be busy when the attendant establishes the requested call.
Absent Subscriber Service is a telephone service provided by local telephone carriers to customers who will be away for a period of time and want to stop the service without losing their telephone number . The calls to the subscriber will be intercepted by a live operator or a machine and a message will be delivered. When the customers come back, they will get their old number. But in the meantime, while they are away, they pay less money per month than they would for normal phone service.
Absolute delay refers to the following: 1. The time interval or phase difference between transmission and reception of a signal. 2. The total time between the instant a bit enters the network and the instant a corresponding bit exists the network
Absorption Band is a range of wavelengths (or, equivalently, frequencies) in the electromagnetic spectrum within which electromagnetic energy is absorbed by a substance. When the absorbing substance is a polyatomic gas, an absorption band actually is composed of a group of discrete absorption lines which appear to overlap. Each line is associated with a particular mode of vibration or rotation induced in a gas molecule by the incident radiation.
Absorption coefficient is measure of the attenuation caused by absorption of energy that results from its passage through a medium. Absorption coefficients are usually expressed in units of reciprocal distance. The sum of the absorption coefficient and the scattering coefficient is the attenuation coefficient.
Absorption Spectrum is a diagram which shows the wavelengths of electromagnetic radiation absorbed by a material. The material could be a gas, a solute or a solid. An absorption spectrum is, in a sense, the inverse of an emission spectrum.
AC/DC Ringing refers to telephone ringing that use both ac and dc voltages and currents.
Access Code (AC) refers to a set of digits or numbers besides regular telephone number dialed on the telephone in order to access some telephone related services. For instance, some phone needs to dial 9 to "access outside line", some long distance carrier needs a special set of code to be connected, etc.
ACA: Automatic Circuit Assurance
Automatic Circuit Assurance (ACA) is a PBX feature that helps one to identify bad trunks. The PBX keeps records of calls of very short and very long duration. If these calls exceed a certain parameter, the attendant is notified. The logic is that a lot of very short calls or one very long call may snidest that a trunk is hung, broken or out of order, The attendant can then physically dial into that trunk and check it.
Automatic Call Back (ACB) is a telephone feature that allows one to instruct the telephone system to retain the called and calling numbers, when encountering a busy situation, to reestablish the call when there is an available line.
Access Attempt is the process by which one or more users interact with a telecommunications system to enable initiation of user information transfer. An access attempt begins with an issuance of an access request by an access originator and ends either in successful access or in access failure.
Access Charge is the charge or fees imposed by a communications service or telephone company for the use of its network.
Access Failure refers to an unsuccessful access in a telecommunications system that results in termination of an access attempt in any manner other than initiation of user information transfer between the intended source and destination (sink) within the specified maximum access time
Access Group refers to a set of phones or terminals that have the same permission to access the phone system, computers and networks.
Access Line refers to a transmission path that continuously connects a subscriber's premises to a switching center, common carrier operating center, or teleprocessing system.
Access link is the local line connecting customer to the central office switch, giving access to a PSTN carrier who will provide the customer dial tone or private line communications services. The access link may be a T1 line, a DSL connection, a cable (CATV) network, a broadband wireless link, or a metro-Ethernet connection.
Access Number refers to "dial-up Numbers" to access to an local Internet Service Provider.
Access Protection refers to the process or means to protect a telephone system local loop against possible outages and failures.
Access Rate refers to the maximum data transmission rate over the access link in a typical network like former AT&T hikes cable access rate.
Account Code is a numeric code that must be entered to dial long distance numbers in some companies to control telephone billing. Account code can protect against telephone abuse and is a way to track calls back to the person or project originating the calls.
Accunet Spectrum Digital Service
Accunet spectrum digital service refers to a former AT&T's leased line digital service as 56 Kbps.
ACD Call Back Massaging is one of the ACD (Automatic Call Distributor) capabilities. It allows callers to leave messages for agents instead of waiting for a live agent. It helps to balance workloads of an agent between peak and off-peak hours.
ACD Caller Directed Call Routing
ACD Caller Directed Call Routing refers to as an auto attendant capability of ACD. It allows callers to direct themselves to the appropriate agent group without the intervention of an operator. By responding to prompts (like pressing certain number on telephone), a caller is automatically routed to the designated agent group.
ACD (Automatic Call Distributor) Central Office refers to an ACD usually located in a central office and supplied to the customer by the telephone company with tariffed pricing structures.
ACD (Automatic Call Distributor) Conditional Routing refers to an ability of ACD that monitors various parameters within the system and call center and to intelligently route calls based on that information conveyed in those parameters like volume levels of calls in queue, the number of agents available, and etc.
ACD Data Directed Call Routing
ACD (Automatic Call Distributor) Data Directed Call Routing refers to an ACD capability that it can automatically process calls based on data provided by a database of information resident in a separate data system.
ACD Intelligent Call Processing
ACD (Automatic Call Distributor) Intelligent Call Processing refers to the features of the ACDs to intelligently route calls according to (1) information provided by the caller, (2) a database on callers and system parameters within the ACD.
ACD (Automatic Call Distributor) Number is the telephone number dialed in order to access any of the multiple agents in an ACD group.
ACD: Automatic Call Distributor
Automatic Call Distributor (ACD) is a telephone facility that manages incoming calls and handles them based on the number called and an associated database of handling instructions. Many companies, offering sales and service support, use ACDs to validate callers, make outgoing responses or calls, forward calls to the right party, allow callers to record messages, gather usage statistics, balance the use of phone lines, and provide other services.
AC-DC Ringing is telephone ringing function/facility that makes use of both AC and DC voltages and currents. An AC may be used to operate a ringer and DC to aid the relay action that stops the ringing when the called telephone is answered.
ACELP: Algebraic Code Excited Linear Prediction
Algebraic Code Excited Linear Prediction (ACELP) is a process employed in analysis by synthesis codecs in order to predict the filter coefficients required to synthesize speech at the receiving party. This process is specified in the ITU-T G723.1 codec specification.
Acoustic Connection is a connection to a device or system made by sound waves. Any system that provides voice communication, such as a telephone set, is an example of Acoustic Connection.
ACSB: Amplitude Compandored Sideband
Amplitude Compandored Sideband (ACSB) is a narrow-band modulation using a single sideband with a pilot tone, allowing an expander in the receiver to restore the amplitude that was severely compressed by the transmitter. (Note that most of the noise reduction circuits used in audio recording are also variations of companding.) This mode promised greater robustness and fade-resistance on HF than even SSB, but was pretty much leapfrogged in favor of spread spectrum, which solves the problem even better.
ACTA: America's Carriers Telecommunications Association
America's Carriers Telecommunications Association (ACTA) is a trade association of "competitive", long distance carriers. One of their purposes is to petition the Federal Communications Commission (FCC) to ban the selling of software and hardware products by some companies that enable use of the Internet to voice long distance services.
Active Call refers to a state of a call in a call processing used in call center which indicates a connection is in any state except "Hold, Null, or Queued".
Active Campaign refers to an out-band calling project that is currently active.
Active Line refers to telecommunication channel or logical communications circuit that is currently established for data or voice transmission.
Active Noise Control is a process to control, reduce or cancel unwanted noise during a call.
Active Participation refers to a feature in a call center which allows intrusion into an agent call by a supervisor who can listen to or join the conversation.
ACTS: Advanced Communications Technologies and Services (Europe)
Advanced Communications technologies and Services (Europe) (ACTS) refers to a programme under the European Community 4th Framework R &TD Programme, collaborative research and technology development in Europe. It is one of the biggest European R&TD investments with around 120 projects in place. The DTI/EPSRC High Performance Interfaces & Protocols (HPIP) LINK programme is the complementary UK initiative.
ACTS: Automatic Coin Telephone Service
Automatic Coin Telephone Service (ACTS) is a public coin-operated telephone service that completes a variety of phone calls, times the calls, and collects payment without the aid of an operator.
Automatic Calling Unit (ACU) is a device that enables equipment, such as computers and card dialers, to originate calls automatically over a telecommunications network.
ACX: Asynchronous Cross-Connect
Asynchronous Cross-connect (ACX) is an ATM specific switch that can connect different ATM-compatible services together.
Average Delay to Abandon (ADA) refers to the time the average caller who abandoned waiting before being abandoned.
ADACC: Automatic Directory Assistance Call Completion
Automatic Directory Assistance Call Completion (ADACC) is a switch feature/application that offers the caller the option of having the DA call automatically completed to the requested listing.
ADAD: Automatic Dialing and Announcing Device
Automatic Dialing and Announcing Device (ADAD) is a device that use a mechanism that sends an unsolicited recorded message to your home or workplace and could leave such a message on your answering machine
Adaptive Channel Allocation refers to a channel allocation scheme in communications system traffic flow control, channel allocation that information-handling capacities of channels are not predetermined but are assigned on demand. Adaptive channel allocation is usually accomplished by means of a multiplexing scheme.
ADAS: Automated Directory Assistance Service
Automated Directory Assistance Service (ADAS) is an application that automates the greeting-and-inquiry portion of the directory assistance call and plays the subscriber's responses to the operator for a savings of 2-4 seconds in worktime.
ADC: Analog-to-Digital Converter
Analog-to-Digital Converter (ADC, A/D or A to D) is an electronic device that converts continuous signals to discrete digital numbers. The reverse operation is performed by a digital-to-analog converter (DAC). ADC can uniquely represents all analog input values within a specified total input range by a limited number of digital output codes.
Add-on Conference is a call feature that allows an additional party to be added to an established call without attendant assistance.
Add-on Data Module is plug-in circuit card enabling a PBX to send and receive analog and digital signals.
Address Complete Message, a CCS/SS7 term, refers to the signaling message that contains call-status information sent prior to the called party going off-hook.
Address Message is a signaling message sent in the forward direction that contains (a) address information, (b) the signaling information required to route and connect a call to the called line, (c) service-class information, (d) information relating to user and network facilities, and (e) call-originator identity or call-receiver identity.
Address Signaling is a process in telecommunication system used to convey address information. There are two address signaling methods, dial pulse (DP) and dual tone multifrequency (DTMF)
Addressed Call Mode permits control signals and commands to establish and terminate calls in V.25bis.
ADE: Adaptive Design Engineering
Adaptive Design Engineering (ADE) is the process of providing specialized design and development of switching, transmission, and customer-premises equipment, or modifications of standard products to meet the specific needs of a customer.
Adjacent Signaling Points refers to two signaling points that are directly interconnected by one or more signaling links.
Add/Drop Multiplexer (ADM), the main building blocks of SONET/SDH networks, combines, or multiplexes, several lower-speed streams of data into a single beam of light. ADMs, upon receipt of an optical signal (OC-n/STM-n), are configured to drop off the whole incoming signal or drop-off only certain lower rate optical signals and/or lower rate PDH signals (T1,T3). The remaining signal passes through. At the same time, optical or PDH signals could be added to replace the dropped-off signal and complete the outgoing optical signal. ADMs can be used both in long-haul core networks and in shorter-distance metro networks. A recent shift in ADM technology has introduced so called multi-service SONET/SDH (also known as a multi-service provisioning platform, or MSPP) equipment which has all the capabilities of legacy ADMs, but can also include cross-connect functionality to manage multiple fiber rings in a single chassis. These new devices can replace multiple legacy ADMs and also allow connections directly from Ethernet LANs to a service provider's optical backbone.
Administrative Trunk Group is a category of trunk groups that provide call status monitoring. The function may be one of revenue protection (i.e., coin overtime collection), protection of the message network from overloads (i.e., no-circuit announcements), and so on.
ADPCM: Adaptive Differential Pulse-Code Modulation
Adaptive Differential Pulse Code Modulation(ADPCM) is the process by which analog voice samples are encoded into high-quality digital signals. The first ADPCM standardized by the CCITT is G.721 for 32 kbps. Later came the standards G.726 and G.727 for 40, 32, 24 and 16 kbps. ADPCM is used to send sound on fiber-optic long-distance lines as well as to store sound along with text, images, and code on a CD-ROM.
Advanced Branch Exchange is an uncommon PBX term refers to a PBX with advanced features normally including the ability to handle both voice and data in some sort of integrated way.
Aerial Cable is transmission facility physically strung between poles or similar over-head structures.
Aeronautical Emergency Communications System Plan
Aeronautical Emergency Communications System Plan is a process that provides for the operation of aeronautical communications stations, on a voluntary, organized basis, to provide the President and the Federal Government, as well as heads of state and local governments, or their designated representatives, and the aeronautical industry with an expeditious means of communications during an emergency situation.
Aggregation Device is a special ISDN terminal adapter. It can aggregate or bond the two B channels into a single higher-speed connection. Sometimes, aggregate device also includes bridges which is the data link layer device connecting two LANs.
Average Handle Time (AHT) is the average time it takes for calls to a service or a skill group to be handled. Handle time includes talk time plus after-call work time.
AIC: Automatic Intercept Center
Automatic Intercept Center (AIC) is a centrally located set of equipment that is a part of an Automatic Intercept System and provides arrangements, having stored program control, whereby the caller is automatically advised, by means of either recorded or electronically assembled announcements, of the situation that prevents the completion of connection to the called number.
As-Is Data Rate (AIDR) is a term primarily used by telephone companies to represent the level of available data throughput that can actually be provided to an end-user over copper wiring. AIDR, as opposed to MEDR ( Maximum Engineering Data Rate) is an actual measure of what an end-user can be provided measured in kilobytes per second—in other words, an AIDR of 3000 means that the end-user in question can receive up to 3000 kilobytes per second of download speed.
AIN: Advanced Intelligent Networks
Advanced Intelligent Network(AIN) is a telephone network architecture that separates service logic from switching equipment, allowing new services to be added without having to redesign switches to support new services. It encourages competition among service providers since it makes it easier for a provider to add services and offers customers more service choices. Developed by Bell Communications Research(Bellcore, now Telcordia), AIN is recognized as a telecom industry standard in North America.
AIOD: Automatic Identified Outward Dialing
Automatic Identified Outward Dialing (AIOD) refers to a service feature of some switching or terminal devices that provides the user with an itemized statement of usage on directly dialed calls. AIOD is facilitated by automatic number identification (ANI) equipment to provide automatic message accounting (AMA).
Air-Ground Worldwide Communications System
Air-ground worldwide communications system is a worldwide military network of ground stations that (a) provides two-way communications links between aircraft and ground stations for navigation and control, including air route traffic control and (b) may also provide support for special functions, such as for civil aircraft providing assistance to military missions and for meeting communications requirements for aircraft flying distinguished visitors.
Alarm Indication Signal (AIS), in a T1 transmission, is an all-ones signal transmitted in lieu of the normal signal to maintain transmission continuity and to indicate to the receiving equipment that there is a transmission interruption located either at the equipment originating the AIS signal or upstream of that equipment. Alarm Indication Signal (AIS) may also refers to a signal transmitted in lieu of the normal signal to maintain transmission continuity and indicate to the receiving terminal that there is a transmission fault located either at the transmitting terminal or upstream of the transmitting terminal.
AIS: Automatic Intercept System
Automatic Intercept System (AIS) is a type of Traffic Service System consisting of one or more automatic intercept centers and a centralized intercept bureau for handling intercept calls.
A-Law is the standard codec (compression/decompression) algorithm for pulse code modulation (PCM) from the ITU-T (the Telecommunication Standardization Sector of the International Telecommunications Union). A-Law is the type of PCM used in most of the world. The other type, mu-Law, is used in the United States and Japan.
Alerting Signal is a signal used by the telephony network to indicate the presence of an incoming call. It consists of a ringing signal periodically interrupted by silent (no ringing signal) intervals.
Alerting Tone is used to indicate that an operator has connected to the line for emergency interrupt on a busy line during a verification call. Alerting Tone is 440 Hz on for 2 seconds and then on again for 5 seconds every ten seconds.
A-link, short of SS7 Access Link, is a dedicated SS7 signaling link not physically associated with any particular link carrying traffic. An A-link connects a signaling end-point (e.g., an SCP or SSP) to an STP. Only messages originating from or destined to the signaling end point are transmitted on an A-link.
All Trunk Busy refers an equipment condition in which all trunks (paths) in a given trunk group are busy. All-trunks-busy registers do not indicate subsequent attempts to reach trunk groups.
Allomorphism is the ability of object instances of a specific class to imitate the behavior of another object class, and allows proprietary extensions. This is a technique for managing the complexity introduced by multiple versions of models.
Alternate Access Carriers, also known as Competitive Local Exchange Carriers(CLEC), are local exchange carriers in direct competition with the RBOCs. They are normally found only in the larger metropolitan areas.
Alternate Mark Inversion Signal
Alternate Mark Inversion Signal is a pseudoternary signal, representing binary digits, in which (a) successive "marks" are of alternately positive and negative polarity and the absolute values of their amplitudes are normally equal and (b) "spaces" are of zero amplitude.
Alternate party, also referred as alternate party diversion, is an optional feature of telephone services, where a call may be routed to a different number based on time-out and precedence schemes set up by the customer.
Administrative Module (AM) is a component of the Lucent 5ESS switch that provides the system-level interfaces required to operate, administer and maintain a 5ESS switch. The functions of the AM are: (1) performs common operations that can be done globally and economically such as resource allocation, maintenance, and control. (2) AM processor is fully duplicated to provide a highly reliable and stable system. (3) performs call-processing support functions (4) performs administrative functions, and provides software access to external data links and disk storage. (5) The call-processing functions of the AM consisted of data routing and recource allocation. Data routing involves determining the SM on which a terminating line or trunk appears and then selecting an available trunk in a trunk group to carrythe traffic. The AM allocates and releases global resources such as TMS time slots to insure efficient operation of the switch. (6) A duplicated disk memory provides mass storage for programs and data. (7) The AM is the only processor in this distributed processing architecture, that keeps an up-to-date picture of the entire system. (8) The master control center (MCC) provides the primary interface between the 5ESS equipment and the pernnel adminstering/maintaining the system.
AMA: Automatic Message Accounting
Automatic Message Accounting (AMA) is a switching feature that automatically records data regarding user-dialed calls. AMA handles the automatic collection, recording, and processing of information relating to calls for billing purposes.
Ambient Noise Level is as it implied the level of acoustic noise existing at a given location, such as in a room, in a compartment, or at a place out of doors. Ambient noise level is measured with a sound level meter. Ambient noise level is usually measured in dB above a reference pressure level of 0.00002 Pa, i.e., 20 Pa (micro-pascals) in SI units. A pascal (Pa) is a Newton per square meter.
American Wire Gauge is a standard method of denoting wire diameter, especially for nonferrous, electrically conducting wire.
Ameritech was one of the seven baby bells spuned off from the former AT&T. Ameritech became SBC and now merged with AT&T again.
Alternate Mark Inversion (AMI) is a synchronous clock encoding technique which uses bipolar pulses to represent logical 1 values. It is, therefore, a three level system. A logical 0 is represented by no symbol, and a logical 1 by pulses of alternating polarity. The alternating coding prevents the build-up of an o.k. voltage level down the cable. This is considered an advantage since the cable may be used to carry a small d.c. current to power intermediate equipment such as line repeaters.
Amplified Handset is the phone handset equipped with amplifier to increase the voice volume.
ANAC Number: Automatic Number Announcement Circuit Number
Automatic Number Announcement Circuit (ANAC) Number is a telephone number that plays back the number of the telephone that carries it. ANAX Numbers are convenient if you wants to know the telephone number of a pair of wires.
Analog Bridge refers to a circuit in telecommunication system like switch that has the capability to extend (bridge) a normal two-person voice conversation to include a third person without degrading the quality of the call
Analog Carrier System is a transmission system that uses repeaters that compensate for analog medium impairments, and produce output signals that are linear-scaled versions of input signals. Analog carrier systems can carry speech, data, video and supervisory signals although they are best suited for speech signals.
Analog Channel is a channel capable of transmitting analog signals within the specified bandwidth of the facility. Voice channels are analog channels.
Analog Data refers to the data represented by a physical quantity that is considered to be continuously variable and has a magnitude directly proportional to the data or to a suitable function of the data.
Analog Decoding is a process, in the electronics context, of converting digital to analog that generates an analog signal value from the digital signal resulted from analog encoding.
Analog Facsimile is a device that can transmit and receive grey shadings. It has the capability of transmitting continuous shades of grey. Analog Facsimile is usually transmitted digitally.
Analog Loop-back is a testing scheme of modem self-test in which data from the keyboard or an internal test pattern is sent to the modem's transmitter, turned into analog form, looped back to the receiver and converted back into digital form
Analog Signal is a signal that has a continuous nature rather than a pulsed or discrete nature. Electrical or physical analogies, such as continuously varying voltages, frequencies, or phases, may be used as analog signals. A nominally continuous electrical signal that varies in some direct correlation with another signal impressed on a transducer. For example, an analog signal may vary in frequency, phase, or amplitude in response to changes in physical phenomena, such as sound, light, heat, position, or pressure.
Analog Switch refers to telephone switching equipment that switches the analog signal without changing its analog nature such as converting the signal into digital signal. Circuit switching is a typical analog switching.
AND: Automatic Network Dialing
Automatic Network Dialing (AND) refers to a feature that simplify on-network calling among multiple business locations by providing a single step dialing for private networks and a single numbering/dialing plan.
ANI: Automatic Number Identification
Automatic Number Identification (ANI) is a system utilized by telephone companies to identify the DN (Directory Number) of a calling subscriber. ANI serves a function similar to Caller-ID, but utilizes different underlying technology. In addition, although Caller-ID blocked by prefixing a call with *67, ANI is (usually) impossible to block. Though ANI is thought of as an ISDN feature, it is actually distinct from ISDN, and is a part of Signaling System 7.
Anisochronous refers to the characteristics of transmission in which the time interval separating any two significant instants in sequential signals is not necessarily related to the time interval separating any other two significant instants.
Answer Message (ANM) is an off-hook signal sent in the reverse direction that indicates when the called party answers. Billing of a call starts when the answer message is received.
Announcement Service refers to the feature/service of telephone system that allows a caller to hear a recoding when they dial a certain phone number or extension.
Announcement System refers to the system or service that provides information to a caller via recorded messages or announcements.
Annoyance Call Bureau is the department in local phone company which handles complain or report about annoyance calls or harassing calls people might receive.
Annunciator is a visual or audible signaling device that indicates the condition and/or availability of associated circuit (s) or stations.
Anonymous Call Rejection refers to a feature that allows you to reject calls from callers who have blocked the display of their telephone numbers. Anonymous Call Rejection discourages anonymous calls, since callers must allow their numbers to be displayed in order to reach you.
Anonymous Telephone Number refers to a phone number that switching systems will handle differently so that it shouldn't be displayed and voiced back to the called party.
ANSA: Alternate Network Service Agreement
Alternate Network Service Agreement (ANSA) is a special arrangement for ISDN service. Under ANSA, customers who reside in areas where the central office switch does not support ISDN can be serviced from a neighboring central office at no additional charge. From the customer's perspective, ISDN is readily available and affordable, but the customer MUST agree to migrate to the local central office if and when service becomes available. In most cases, this will involve a change in phone number. This agreement pertains to former Bell South customers only.
Answer Back is a specific identifying code, automatically transmitted by an addressed station upon the receipt of a special request signal from the originating station (or system).
APON: ATM Passive Optic Network
ATM Passive Optic Network (APON), also known as Broadband PON (BPON), is the initial PON specification defined by the FSAN committee used ATM as their layer 2 signaling protocol. Use of the term APON led users to believe that only ATM services could be provided to end-users, so the FSAN decided to broaden the name to Broadband PON (BPON). BPON systems offer numerous broadband services including Ethernet access and video distribution.
APS: Automatic Protection System
Automatic Protection System (APS) is a switching architecture designed for SONET (Synchronous Optical Network ) to perform error protection and network management from any point of the signal path.
Area Code is a three-digit number (the first three digits in the phone number xxx-xxx-xxxx) identifying one of the assigned geographic areas in the North American direct assistance dialing numbering plan.
Area Exchange is a geopolitical area setup for the administration of local telephone service, usually a single metropolitan area or collection of towns and villages sharing a common area of community interest.
Arithmetic Shift refers to a shift, applied to the representation of a number in a fixed-radix numeration system and in a fixed-point representation system, and in which only the characters representing the fixed-point part of the number are moved. An arithmetic shift is usually equivalent to multiplying the number by a positive or a negative integral power of the radix, except for the effect of any rounding; compare the logical shift with the arithmetic shift, especially in the case of floating-point representation.
ARQ: Automatic Repeat & Request
Automatic Repeat-reQuest (ARQ) is an error control method for data transmission in which the receiver detects transmission errors in a message and automatically requests a retransmission from the transmitter. Usually, when the transmitter receives the ARQ, the transmitter retransmits the message until it is either correctly received or the error persists beyond a predetermined number of retransmissions. A few types of ARQ protocols are Stop-and-wait ARQ, Go-Back-N ARQ and Selective Repeat ARQ.
Articulation Score (AS) is a subjective measure of the intelligibility of a voice system in terms of the percentage of words correctly understood over a channel perturbed by interference. Articulation scores have been experimentally obtained as functions of varying word content, bandwidth, audio signal-to-noise ratio and the experience of the talkers and listeners involved.
Average Speed of Answer (ASA), also called Average Seconds to Answer or Average Time to Answer (ATA), is the average answer waiting time for all calls to a service in a given period (e.g. the last 15 minutes, today, this month). It is the total amount of time all calls waited to be answered divided by the total number of calls. It is often expressed in seconds.
ASC: Accredited Standards Committees
Accredited Standards Committees (ASC) is an IEEE committee accredited to develop standards. The committee consists of members and a Secretariat. The membership is generally composed of organizations, companies, government agencies, individuals, etc. having a direct and material interest in the activities of the committee. A balance of the various interest groups must be maintained, i.e., no one interest group can dominate the committee. The Secretariat is an organization that has oversight responsibilities over the ASC. The Secretariat organizes the committee, applies for its accreditation, oversees the committees' compliance to procedures, maintains the roster, submits standards for approval, publishes the standards, etc.
ASE: Application Service Element
Application Service Element (ASE) is the function that allows applications to communicate with one another in a SS7 system. Examples of an ASE include TCAP (Transaction Capabilities Application Part) and MAP (Mobile Application Part).
Amplitude Shift Keying (ASK) is a modulation process which imparts to a carrier wave (sinusoid) two or more discrete amplitude levels. These are related to the number of levels adopted by the digital message
AT&T Switched Network (ASN) refers to the former AT&T Global Network which was the most sophisticated communications network in the world. On an average business day, it had delivered more combined data, voice and internet traffic to more locations, more reliably, than any other network. It had handled more than 3.8 Petabytes (Peta = Quadrillion) of data every 7.5 minutes-as well as 410 million voice calls.
ASP: Application Service Provider
Application Service Provider (ASP) refers to the business which provides software service based on network especially over the Web. It's a new way to sell and distribute software services in the Internet age. The ASP model can be appealing to businesses -- especially small businesses and startups -- because it can drastically lower the costs of software and services.
Associated Mode refers to one of the three common channel signaling modes. In the Associated Mode, messages for signaling functions (which involve adjacent signaling points) are transported over a direct interconnecting link.
Associative Storage is a storage device or process that the storage locations are identified by their contents, or by a part of their contents, rather than by their names or positions. This is also known as content-addressable storage.
Asynchronous Operation refers to operations which are executed in computer out of time coincidence with any event. An operation that occurs without a regular or predictable time relationship to a specified event; e.g., the calling of an error diagnostic routine that may receive control at any time during the execution of a computer program.
Access Tandem (AT) refers to a telephone switch that interconnects with CO (Central Office) switches and other access tandem switches to form the PSTN (Public Switched Telephone Network). It is often called a "class 4" switch, a reference to the original AT&T hierarchal network structure.
Analog Terminal Adapter (ATA) is a device that allows a normal PSTN telephone to connect to the Internet in order to make or place telephone calls. An ATA device may work in conjunction with a computer, such as a USB ATA device, or it may be a stand-alone device that communicates with a service provider over the Internet. The latter types of devices are common with many broadband VoIP service providers.
Average Time to Answer (ATA), also called Average Speed of Answer (ASA) or Average Seconds to Answer is the average answer wait time for all calls to a service in a given period (e.g. the last 15 minutes, today, this month). It is the total amount of time all calls waited to be answered divided by the total number of calls. It is often expressed in seconds.
All Trunks Busy (ATB) is the state of a trunk group when all trunks are in use. The trunk group cannot accept any new inbound or outbound calls in this state.
ATDM: Asynchronous Time-Division Multiplexing
Asynchronous time-division multiplexing (ATDM) is a method of sending information that resembles normal TDM, except that time slots are allocated as needed dynamically rather than preassigned to specific transmitters. ATDM is more intelligent and has better bandwidth efficiency than TDM.
ATIS: Alliance for Telecom Industry Solutions
Alliance for Telecom Industry Solutions (ATIS) is a standards body that developing telecommunications standards, operating procedures and guidelines through its sponsored committees and forums. ATIS member companies are North American providers of telecommunications services, and including wireline and wireless service providers, competitive local carriers, inter-exchange companies, local exchange companies, manufacturers, software developers, resellers, enhanced service providers, and providers of operations support.
Attack Time is the time between (a) the instant that a signal at the input of a device or circuit exceeds the activation threshold of the device or circuit and (b) the instant that the device or circuit reacts in a specified manner, or to a specified degree, to the input. Attack time occurs in devices such as clippers, peak limiters, compressors, and voxes.
Attempt, in telecommunication context, refers to a call offered to a telecommunications system, whether or not it is completed.
Attenuation Constant refers to the following definition:
1. The real part of the propagation constant in any electromagnetic propagation medium. The attenuation constant is usually expressed as a numerical value per unit length and may be calculated or experimentally determined for each medium.
2. For a particular propagation mode in an optical fiber, the real part of the axial propagation constant.
Attenuation to crosstalk ratio
Attenuation to crosstalk ratio is the difference between attenuation and crosstalk at a given frequency along a cable. Measured in decibels, ACR is a calculation used in networking transmission to assure that a signal transmitted across a twisted-pair cable is stronger at the receiving end than any interference signals imposed on that same pair by crosstalk from adjacent pairs.
ATU-C: ADSL Transmission Unit-Central Office
ADSL Transmission Unit-Central Office (ATU-C) refers to the modem of the central office that is a component of the ADSL network. It terminates the ADSL (Asymmetric Digital Subscriber Line) local loop at the central office premises.
ATU-R: ADSL Transmission Unit-Remote
ADSL Transmission Unit-Remote (ATU-R) refers to the modem at the customer premises which is a component of the ADSL network. It provides local loop termination on the customer side
Audible busy tone is one of the audible tones in telephone system to signal a busy status. The "Precise" busy signal (Real Audio) / "Precise" busy signal (WAV): 480 and 620 Hz at -24 dBm0/frequency, is generated at telephone exchange, interrupted at 60 interruptions per minute (0.5 sec. on, 0.5 sec. off).
Audible Ring Tone is a ringing indication which is intercepted by the calling party to mean that the called line has been reached and that the ringing has started. It is also used on calls to operators (special service, long distance, intercepting, etc) during the "awaiting-operator-answer" interval. Audible Ring Tone is 440 Hz and 480 Hz for 2 seconds on and 4 seconds off at -13 dBm0/frequency.
Audible tones refer to the audible signal used in the telephone system to indicate the progress or disposition of a call. These include dial tone, busy tone, reorder tone, ring back and call waiting. It could be generated by either the called-party servicing switch or by the calling-party servicing switch.
Audit refers to the following actions in telecommunication system: 1. To conduct an independent review and examination of system records and activities in order to test the adequacy and effectiveness of data security and data integrity procedures, to ensure compliance with established policy and operational procedures, and to recommend any necessary changes.2. Independent review and examination of records and activities to assess the adequacy of system controls, to ensure compliance with established policies and operational procedures, and to recommend necessary changes in controls, policies, or procedures.
Automatic Call Reconnect is a feature permitting automatic call rerouting away from a failed trunk line.
Automatic sounding is the testing of selected channels or paths by providing a very brief beacon-like identifying broadcast that may be used by other stations to evaluate connectivity, propagation, and availability, and to identify known working channels for possible later use for communications or calling. Automatic soundings are primarily intended to increase the efficiency of the automatic link establishment (ALE) function, thereby the system throughput. Sounding information is used for identifying the specific channel to be used for a particular ALE connectivity attempt.
Automatic Switching System refers to: 1. a telephony system in which all the operations required to set up, supervise, and release connections required for calls are automatically performed in response to signals from a calling device. 2. a data communication switching system in which all the operations required to execute the three phases of information-transfer transactions are automatically executed in response to signals from a user-end instrument. In an automatic switching system, the information-transfer transaction is performed without human intervention, except for initiation of the access phase and the disengagement phase by a user.
Auxiliary Service Trunk Groups
Auxiliary Service Trunk Groups is a category of trunk groups that provide selected services for customers or operators and terminate at announcement systems, cord switch boards, or desks. Typical applications commonly employ the following types of trunk groups: Direct Assistance, Intercept, Official, Public Announcement, Rate-and-Route, Repair Service, Timeo Weather.
Available Line is a circuit between two points that is ready for service, but is in the idle state. In facsimile transmission, available Line is the portion of the scanning line that can be specifically used for image signals.
Advanced Voice Busyout(AVBO) is the local voice busy-out feature in a PBX or other Customer Premises Equipment (CPE). AVBO provides a way to busy out a voice port or a time slot if a state change is detected in a monitored network interface. When a monitored interface changes to a specified state, to out-of-service, or to in-service, the voice port presents a seized/busy-out condition to the attached PBX or other CPE. The PBX or other CPE can then attempt to select an alternate route. AVBO adds the following functionality to the local voice busy-out feature: 1) For Voice over IP (VoIP), monitoring of links to remote, IP-addressable interfaces by the use of a real time reporter (RTR). 2) Configuration by voice class to simplify and speed up the configuration of voice busy-out on multiple voice ports. 3) Local voice busy-out is supported on analog and digital voice ports using channel-associated signalling (CAS).
Average Load is the load obtained by averaging a series of hourly loads; may be further defined as average carried load, average offered load. This term is not to be confused with load, which is inherently an average of all the instantaneous loads over a basic time interval, such as an hour.
AXE is an Ericsson’s communications platform, a system for computer-controlled digital exchanges in large public telecommunications networks. This is the basis for Ericsson't wireline and mobile systems.