Abandoned Call

Also called a Lost Call. The caller hangs up before reaching an agent.

Activity Codes

See Wrap-Up Codes.


The person who handles incoming or outgoing calls. Also referred to as customer service representative (CSR), telephone sales or service representative (TSR), rep, associate, consultant, engineer, operator, technician, account executive, team member, customer service professional, staff member, attendant and specialist. Did we miss any?

Agent Group

Also called Split, Gate, Queue or Skills Group. A collection of agents that share a common set of skills, such as being able to handle customer complaints.

Agent Out Call

An outbound call placed by an agent.

Agent Status

The mode an agent is in (Talk Time, Wrap, Unavailable, etc.).


Telephone transmission or switching that is not digital. Signals are analogous to the original signal.


A recorded verbal message played to callers.

Answered Call

When referring to an agent group, a call counted as answered when it reaches an agent.

Application Based Routing and Reporting

The ACD capability to route and track transactions by type of call, or application (e.g., sales, service, etc.), versus the traditional method of routing and tracking by trunk group and agent group.

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The basic design of a system. Determines how the components work together, system capacity, upgradeability, and the ability to integrate with other systems.

Auto Available

An ACD feature whereby the ACD is programmed to automatically put agents into Available after they finish Talk Time and disconnect calls. If they need to go into Wrap, they have to manually put themselves there. See Auto Wrap-up.

Auto Greeting

Agent's pre-recorded greeting that plays automatically when a call arrives.

Auto Wrap-up

An ACD feature whereby the ACD is programmed to automatically put agents into After-Call Work after they finish Talk Time and disconnect calls. When they have completed any After-Call Work required, they put themselves back into Available. See Auto Available.

Automatic Call Distributor

The specialized telephone system used in incoming call centres. It is a programmable device that automatically answers calls, queues calls, distributes calls to agents, plays delay announcements to callers and provides real-time and historical reports on these activities. May be a stand-alone system, or ACD capability built into a CO, network or PBX.

Automatic Call Sequencer

A simple system that is less sophisticated than an ACD, but provides some ACD-like functionality.

Auxiliary Work State

An agent work state that is typically not associated with handling telephone calls. When agents are in an auxiliary mode, they will not receive inbound calls.


See Adherence to Schedule.

Available State

Agents who are signed on to the ACD and waiting for calls to arrive.

Available Time

The total time that an agent or agent group waited for calls to arrive, for a given time period.

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Average Delay

See Average Speed of Answer.

Average Delay of Delayed Calls

The average delay of calls that are delayed. It is the total Delay for all calls divided by the number of calls that had to wait in queue. See Average Speed of Answer.

Average Handle Time

The sum of Average Talk Time and Average After-Call Work for a specified time period. .

Average Number of Agents

The average number of agents logged into a group for a specified time period.

Average Speed of Answer

Also called Average Delay. The average delay of all calls. It is total Delay divided by total number of calls. See Average Delay of Delayed Calls.

Average Time to Abandonment

The average time that callers wait in queue before abandoning. The calculation considers only the calls that abandon.

Base Staff

Also called Seated Agents. The minimum number of agents required to achieve service level and response time objectives for given period of time. Seated agent calculations assume that agents will be in their seats for the entire period of time. Therefore, schedules need to add in extra people to accommodate breaks, absenteeism and other factors that will keep agents from the phones. See Rostered Staff Factor.

Beep Tone

An audible notification that a call has arrived (also called Zip Tone). Beep tone can also refer to the audible notification that a call is being monitored.


Historically, a term referred to as a standardized task to test the capabilities of devices against each other. In quality terms, benchmarking is comparing products, services and processes with those of other organizations, to identify new ideas and improvement opportunities.

Best in Class

A benchmarking term to identify organizations that outperform all others in a specified category.

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Callers blocked from entering a queue. See Blocked Call.

Blocked Call

A call that cannot be connected immediately because A) no circuit is available at the time the call arrives, or B) the ACD is programmed to block calls from entering the queue when the queue backs up beyond a defined threshold.

Busy Hour

A telephone traffic engineering term, referring to the hour of time in which a trunk group carries the most traffic during the day. The average busy hour reflects the average over a period of days, such as two weeks. Busy Hour has little use for incoming call centres, which require more specific resource calculation methodologies.


Also called Transaction and Customer Contact. A term referring to telephone calls, video calls, Web calls and other types of contacts.

Call Blending

Combining traditionally separate inbound and outbound agent groups into one group of agents responsible for handling both inbound and outbound contacts. A system that is capable of call blending automatically puts agents who are making outbound calls into the inbound mode and vice versa, as necessitated by the incoming call load.

Call By Call Routing

The process of routing each call to the optimum destination according to real-time conditions. See Percent Allocation and Network Inter-flow.

Call Centre

An umbrella term that generally refers to reservations centres, help desks, information lines or customer service centres, regardless of how they are organized or what types of transactions they handle. The term is being challenged by many, because calls are just one type of transaction and the word centre doesn't accurately depict the many multi-site environments.

Call Control Variables

The set of criteria the ACD uses to process calls. Examples include routing criteria, overflow parameters, recorded announcements and timing thresholds.

Call Detail Recording

Data on each call, captured and stored by the ACD. Can include trunk used, time in queue, call duration, agent who handled the call, number dialed (for outgoing), and other information.

Call Forcing

An ACD feature that automatically delivers calls to agents who are available and ready to take calls. They hear a notification that the call has arrived (e.g. a beep tone), but do not have to press a button to answer the call.

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Call Load

Also referred to as Work Load. Call Load is the product of (Average Talk Time + Average After-Call Work) x call volume, for a given period.

Caller-Entered Digits

Digits callers enter using their telephone keypads. The ACD, IVR, or network can prompt for CEDs.

Calling Line Identity

A telephone network feature that passes the number of the phone the caller is using to the call centre, real-time. CLI may arrive over the D channel of an ISDN PRI circuit (out of band signaling), or before the first ring on a single line (inband signaling). CLI is delivered from long distance companies. Caller ID is the local phone company version of CLI, and is delivered inband.

Calls In Queue

A real-time report that refers to the number of calls received by the ACD system but not yet connected to an agent.


A company that provides telecommunications circuits. Carriers include both local telephone companies and long distance providers.

Cause-and-Effect Diagram

A tool to assist in root cause identification, developed by Dr. Kaoru Ishikawa.


Compact Disc Read Only Memory. These discs hold as much as 660 megabytes of memory.


A transmission path between two points in a network.

Client/Server Architecture

A network of computers that share capabilities and devices.

Collateral Duties

Non-phone tasks (e.g., data entry) that are flexible, and can be scheduled for periods when call load is slow.

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See Adherence to Schedule.

Computer Simulation

A computer technique to predict the outcome of various events in the future, given many variables. When there are many variables, simulation is often the only way to reasonably predict the outcome.

Computer Telephony Integration

The software, hardware and programming necessary to integrate computers and telephones so they can work together seamlessly and intelligently.

Conditional Routing

The capability of the ACD to route calls based on current conditions. It is based on "if-then" programming statements. For example, "if the number of calls in agent group 1 exceeds 10 and there are at least 2 available agents in group two, then route the calls to group two."

Continuous Improvement

The ongoing improvement of processes.

Control Chart

A control chart sifts out (identifies) two types of variation in a process, common causes and special causes. See Common Causes and Special Causes.

Controlled Busies

The capability of the ACD to generate busy signals when the queue backs up beyond a programmable threshold.

Cost centre

An accounting term that refers to a department or function in the organization that does not generate profit. See Profit centre.

Cost Per Call

Total costs (fixed and variable) divided by total calls for a given period of time.

Customer Contact

See Call.

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Database Call Handling

A CTI application, whereby the ACD works in sync with the database computer to process calls, based on information in the database. For example, a caller inputs digits into a voice processing system, the database retrieves information on that customer and then issues instructions to the ACD on how to handle the call (e.g., where to route the call, what priority the call should be given in queue, the announcements to play, etc.).

Day of Week Routing

A network service that routes calls to alternate locations, based on the day of week. There are also options for day of year and time of day routing.

Delay Announcements

Recorded announcements that encourage callers to wait for an agent to become available, remind them to have their account number ready, and provide information on access alternatives. In some systems, delay announcements are provided through recorded announcement routes (RANs).


Also called Queue Time. The time a caller spends in queue, waiting for an agent to become available. Average Delay is the same thing as Average Speed of Answer. Also see Average Delay of Delayed Calls.

Delayed Call

A call which cannot be answered immediately and is placed in queue.

Dialed Number

The number that the caller dialed to initiate the call.

Dialed Number Identification Service

A string of digits that the telephone network passes to the ACD, IVR or other devise, to indicate which number the caller dialed. The ACD can then process and report on that type of call according to user-defined criteria. One trunk group can have many DNIS numbers.


The use of a binary code '1's and '0's to represent information.

Direct Call Processing

See Talk Time.

Dual-Tone Multifrequency

A signaling system that sends pairs of audio frequencies to represent digits on a telephone keypad.

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Dynamic Answer

An ACD feature that automatically reconfigures the number of rings before the system answers calls, based on real-time queue information. Since costs don't begin until the ACD answers calls, this feature can save callers or the call centre money when long distance charges apply.

Electronic Mail (E-mail)

Electronic text mail.

Envelope Strategy

A strategy whereby enough agents are scheduled for the day or week to handle both the inbound call load and other types of work. Priorities are based on the inbound call load. When call load is heavy, all agents handle calls, but when it is light, some agents are reassigned to work that is not as time-sensitive.

Erlang B

A formula developed by A.K. Erlang, widely used to determine the number of lines required to handle a known calling load during a one hour period. The formula assumes that if callers get busy signals, they go away forever, never to retry ('lost calls cleared'). Since some callers retry, Erlang B can underestimate lines required. However, Erlang B is generally accurate in situations with few busy signals.

Erlang C

Calculates predicted waiting times (delay) based on three things: the number of servers (reps); the number of people waiting to be served (callers); and the average amount of time it takes to serve each person. It can also predict the resources required to keep waiting times within targeted limits. Erlang C assumes no lost calls or busy signals, so it has a tendency to overestimate staff required.

Erlang, A.K

A Danish engineer who worked for the Copenhagen Telephone Company in the early 1900s and developed Erlang B, Erlang C and other telephone traffic engineering formulas.


One hour of telephone traffic in an hour of time. For example, if circuits carry 120 minutes of traffic in an hour, that's two Erlangs.

Error Rate

Either the number of defective transactions or the number of defective steps in a transaction.

Escalation Plan

A plan that specifies actions to be taken when the queue begins to build beyond acceptable levels.

Exchange Line

See Trunk.

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Executive Summary

A brief summary of the key points of a more detailed report or study.

Facsimile / FAX

Technology that scans a document, encodes it, transmits it over a telecommunications circuit, and reproduces it in original form at the receiving end.

Fast Clear Down

A caller who hangs up immediately when they hear a delay announcement.

Fax on Demand

A system that enables callers to request documents, using their telephone keypads. The selected documents are delivered to the fax numbers they specify.


A step by step diagram of a process.

Flushing Out the Queue

Changing system thresholds so that calls waiting for an agent group are redirected to another group with a shorter queue or available agents.

Full-Time Equivalent

A term used in scheduling and budgeting, whereby the number of scheduled hours is divided by the hours in a full work week. The hours of several part time agents may add up to one FTE.


See Agent Group.


A server dedicated to providing access to a network.

Grade of Service

The probability that a call will not be connected to a system because all lines are busy. Grade of service is often expressed as "p.01" meaning 1% of calls will be "blocked." Sometimes, grade of service is used interchangeably with service level, but the two terms have different meanings. See Service Level.

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Handled Calls

The number of calls received and handled by agents or peripheral equipment. Handled calls does not include calls that abandon or receive busy signals.

Handling Time

The time an agent spends in Talk Time and After-Call Work, handling a transaction. Handling Time can also refer to the time it takes for a machine to process a transaction.

Help Desk

A term that generally refers to a call centre set up to handle queries about product installation, usage or problems. The term is most often used in the context of computer software and hardware support centres.

Historical Reports

Reports that track call centre and agent performance over a period of time. Historical reports are generated by ACDs, third party ACD software packages, and peripherals such as IVRs and Call Detail Recording Systems. The amount of history that a system can store varies by system.

Holding Time

See Average Holding Time on Lines.

Home Agent

See Telecommuting


A process whereby documents are scanned into a system and stored electronically.

Immutable Law

A law of nature that is fundamental, and not changeable (e.g., the law of gravity). In an inbound call centre, the fact that occupancy goes up when service level goes down, is an immutable law.

Incoming Call centre Management

The art of having the right number of skilled people and supporting resources in place at the right times to handle an accurately forecasted workload, at service level and with quality.

Incremental Revenue (Value) Analysis

A methodology that estimates the value (cost and revenue) of adding or subtracting an agent.

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Index Factor

In forecasting, a proportion used as a multiplier to adjust another number.

Integrated Services Digital Network

A set of international standards for telephone transmission. ISDN provides an end-to-end digital network, out-of-band signaling, and greater bandwidth than older telephone services. The two standard levels of ISDN are Basic Rate Interface (BRI) and Primary Rate Interface (PRI). See Basic Rate Interface and Primary Rate Interface.

Inter Exchange Carrier

A long-distance telephone company.

Interactive Voice Response

See Voice Response Unit.


See overflow.

Internal Help Desk

A group that supports other internal agent groups, e.g. for complex or escalated calls.

Internal Response Time

The time it takes an agent group that supports other internal groups (e.g., for complex or escalated tasks) to respond to transactions that do not have to be handled when they arrive (e.g., correspondence or e-mail). See Response Time and Service Level.

Internet "Call Me" Transaction

A transaction that allows a user to request a callback from the call centre, while exploring a Web page. Requires interconnection of the ACD system and the Internet by means of an Internet Gateway.

Internet "Call Through" Transaction

The ability for callers to click a button on a Web site and be directly connected to an agent while viewing the site.

Internet Phone

Technology that enables users of the Internet's World Wide Web to place voice telephone calls through the Internet, thus by-passing the long distance network.

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See overflow. Invisible Queue. When callers do not know how long the queue is or how fast it is moving. See Visible Queue.

Judgmental Forecasting

Goes beyond purely statistical techniques and encompasses what people believe is going to happen. It is in the realm of intuition, interdepartmental committees, market research and executive opinion.

Law of Diminishing Returns

The declining marginal improvements in service level that can be attributed to each additional agent, as successive agents are added.

Load Balancing

Balancing traffic between two or more destinations.

Local Area Network

The connection of multiple computers within a building, so that they can share information, applications and peripherals. See Wide Area Network.

Local Exchange Carrier

Telephone companies responsible for providing local connections and services.

Logged On

A state in which agents have signed on to a system (made their presence known), but may or may not be ready to receive calls.

Long Call

For staffing calculations and traffic engineering purposes, calls that approach or exceed thirty minutes.

Longest Available Agent

A method of distributing calls to the agent who has been sitting idle the longest. With a queue, Longest Available Agent becomes 'Next Available Agent'.

Longest Delay (Oldest Call)

The longest time a caller has waited in queue, before abandoning or reaching an agent.

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Look Ahead Queuing

The ability for a system or network to examine a secondary queue and evaluate the conditions, before overflowing calls from the primary queue.

Look Back Queuing

The ability for a system or network to look back to the primary queue after the call has been overflowed to a secondary queue, and evaluate the conditions. If the congestion clears, the call can be sent back to the initial queue.

Lost Call

See Abandoned Call.


Software that mediates between different types of hardware and software on a network, so that they can function together.


A contraction of the terms Modulator/Demodulator. A Modem converts analog signals to digital and vice versa.


Also called Position Monitoring or Service Observing. The process of listening to agents' telephone calls for the purpose of maintaining quality. Monitoring can be: A) silent, where agents don't know when they are being monitored, B) side by side, where the person monitoring sits next to the agent and observes calls or C) record and review, where calls are recorded and then later played back and assessed.

Multilingual Agents

Agents that are fluent in more than one language.


Combining multiple forms of media in the communication of information. (E.g, a traditional phone call is "monomedia," and a video call is "multimedia.")

Murphy's Law

If anything can go wrong, it will. Not a good perspective to live by, but worth considering when designing agent groups, routing configurations and disaster recovery plans.

Network Control centre

Also called Traffic Control centre. In a networked call centre environment, where people and equipment monitor real-time conditions across sites, change routing thresholds as necessary, and coordinate events that will impact base staffing levels.

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Network Inter-flow

A technology used in multi-site call centre environments to create a more efficient distribution of calls between sites. Through integration of sites using network circuits (such as T1 circuits) and ACD software, calls routed to one site may be queued simultaneously for agent groups in remote sites. See Call by Call Routing and Percent Allocation.

Next Available Agent

A call distribution method that sends calls to the next agent who becomes available. The method seeks to maintain an equal load across skill groups or services. When there is no queue, Next Available Agent reverts to Longest Available Agent.

Noise Canceling Headset

Headsets equipped with technology that reduces background noise.

Non ACD In Calls

Inbound calls which are directed to an agent's extension, rather than to a general group. These may be personal calls or calls from customers who dial the agents' extension numbers.


Also referred to as agent utilization. The percentage of time agents handle calls versus wait for calls to arrive. For a half-hour, the calculation is: (call volume x average handling time in seconds) / (number of agents x 1800 seconds). See Adherence to Schedule.

Off The Shelf

Hardware or software programs that are commercially available and ready for use "as is."

Offered Calls

All of the attempts callers make to reach the call centre. There are three possibilities for offered calls: 1) they can get busy signals, 2) they can be answered by the system, but hang up before reaching a rep, 3) they can be answered by a rep. Offered call reports in ACDs usually refer only to the calls that the system receives.


Periods of time other than the call centre's busiest periods. Also a term to describe periods of time when long distance carriers provide lower rates.

Open Ticket

A customer contact (transaction) that has not yet been completed or resolved (closed).


Contracting some or all call centre services to an outside company.

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Calls that flow from one group or site to another. More specifically, Intraflow happens when calls flow between agent groups and Interflow is when calls flow out of the ACD to another site.


See Rostered Staff Factor.

Pareto Chart

A bar chart that arranges events in order of frequency. Named after 19th century economist Vilfredo Pareto.


A PBX that is equipped with ACD functionality.

Peaked Call Arrival

A surge of traffic beyond random variation. It is a spike within a short period of time.

Percent Allocation

A call routing strategy sometimes used in multi-site call centre environments. Calls received in the network are allocated across sites based on user-defined percentages. See Call by Call Routing and Network Inter-flow.

Percent Utilization

See Occupancy.


A formula sometimes used for calculating lines. Assumes that if callers get busy signals, they keep trying until they successfully get through. Since some callers won't keep retrying, Poisson can overestimate lines required. See Erlang B and Retrial Tables.

Pooling Principle

The Pooling Principle states: Any movement in the direction of consolidation of resources will result in improved traffic-carrying efficiency. Conversely, any movement away from consolidation of resources will result in reduced traffic-carrying efficiency.

Position Monitoring

See Monitoring.

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Post Call Processing

See After-Call Work.

Predictive Dialing

A system that automatically places outbound calls and delivers answered calls to agents. When the dialer detects busy signals, answering machines or ring no answer, it puts the number back in queue.

Primary Rate Interface

One of two levels of ISDN service. In North America, PRI typically provides 23 bearer channels for voice and data and one channel for signaling information (commonly expressed as 23B+D). In Europe, PRI typically provides 30 bearer lines (30B+D). See Basic Rate Interface and Integrated Services Digital Network.

Private Automatic Branch Exchange

See Private Branch Exchange.

Private Branch Exchange

A telephone system located at a customer's site that handles incoming and outgoing calls. ACD software can provide PBXs with ACD functionality. Also called private automatic branch exchange (PABX).

Private Network

A network made up of circuits for the exclusive use of an organization or group of affiliated organizations. Can be regional, national or international in scope and are common in large organizations.


A system of causes.

Profit centre

An accounting term that refers to a department or function in the organization that does not generate profit. See Cost centre.

Public Switched Network

The public telephone network which provides the capability of interconnecting any home or office with any other.

Quantitative Forecasting

Using statistical techniques to forecast future events. The major categories of quantitative forecasting include Time Series and Explanatory approaches. Time Series techniques use past trends to forecast future events. Explanatory techniques attempt to reveal linkages between two or more variables. See Judgmental Forecasting.

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Holds callers until an agent becomes available. Queue can also refer to a line or list of items in a system waiting to be processed (e.g., e-mail messages).

Queue Display

See Readerboard.

Queue Time

See Delay.

Random Call Arrival

The normal, random variation in how incoming calls arrive. See Peaked Call Arrival.


Also called displayboards or wall displays. A visual display, usually mounted on the wall or ceiling, that provides real-time and historical information on queue conditions, agent status and call centre performance.

Real-Time Adherence Software

Software that tracks how closely agents conform to their schedules. See Adherence to Schedule.

Real-Time Data

Information on current conditions. Some "real-time" information is real-time in the strictest sense (e.g., calls in queue and current longest wait). Some real-time reports require some history (e.g. the last x calls or x minutes) in order to make a calculation (e.g. service level and average speed of answer). See Screen Refresh.

Real-Time Management

Making adjustments to staffing and thresholds in the systems and network, in response to current queue conditions.

Received Calls

A call detected and seized by a line. Received calls will either abandon or be answered by an agent.

Record and Review Monitoring

See Monitoring.

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Recorded Announcement Route

See Delay Announcement.


A term popularized by management consultant Michael Hammer, which refers to radically redesigning processes to improve efficiency and service.

Response Time

The time it takes the call centre to respond to transactions that do not have to be handled when they arrive (e.g., correspondence or e-mail). See Service Level.

Retrial Tables

Sometimes used to calculate lines and other system resources required. They assume that some callers will make additional attempts to reach the call centre if they get busy signals. See Erlang B and Poisson.


A caller who "retries" when they get a busy signal.

Rostered Staff Factor

Alternatively called an Overlay, Shrink Factor or Shrinkage. RSF is a numerical factor that leads to the minimum staff needed on schedule over and above base staff required to achieve your service level and response time objectives. It is calculated after base staffing is determined and before schedules are organized, and accounts for things like breaks, absenteeism and ongoing training.

Round Robin Distribution

A method of distributing calls to agents according to a predetermined list. See Next Available Agent and Longest Waiting Agent.

Scatter Diagram

A chart that graphically depicts the relationship between two variables.

Schedule Compliance

See Adherence to Schedule.

Scheduling Exception

When an agent is involved in an activity outside of the normal, planned schedule.

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Screen Monitoring

A system capability that enables a supervisor or manager to remotely monitor the activity on agents' computer terminals.

Screen Pop

A CTI capability. Callers' records are automatically retrieved (based on ANI or digits entered into the IVR) and delivered to agents, along with the calls.

Screen Refresh

The rate at which real-time information is updated on a display (e.g. every 5 to 15 seconds). Note, screen refresh does not correlate with the time-frame used for real-time calculations. See Real-Time Data.

Seated Agents

See Base Staff.

Service Bureau

A company that handles inbound or outbound calls for another organization.

Service Level Agreement

Performance objectives reached by consensus between the user and the provider of a service, or between an outsourcer and an organization. A service level agreement specifies a variety of performance standards that may or may not include "service level." See Service Level.

Service Level

Also called Telephone Service Factor, or TSF. The percentage of incoming calls that are answered within a specified threshold: "X% of calls answered in Y seconds." See Response Time.

Service Observing

See Monitoring.

Shrink Factor

See Rostered Staff Factor.

Silent Monitoring

See Monitoring.

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Skill Group

See Agent Group.

Skill-Based Routing

An ACD capability that matches a caller's specific needs with an agent that has the skills to handle that call, on a real-time basis.

Smooth Call Arrival

Calls that arrive evenly across a period of time. Virtually non-existent in incoming environments.

Special Causes

Variation in a process caused by special circumstances. See Common Causes.

Speech Recognition

The capability of a voice processing system to decipher spoken words and phrases.


See Agent Group.

Supervisor Monitor

Computer monitors that enable supervisors to monitor the call handling statistics of their supervisory groups or teams.


The person who has front-line responsibility for a group of agents. Typical ratios are one supervisor to every 10-15 agents. However, help desks can have one supervisor for every 5 people, and some reservations centres have one supervisor for every 30 or 40 agents. Generally, supervisors are equipped with special telephones and computer terminals that enable them to monitor agent activities.

T1 Circuit

A high speed digital circuit used for voice, data or video, with a bandwidth of 1.544 megabits per second. T1 circuits offer the equivalent of twenty-four (24) analog voice lines.

Talk Time

The time an agent spends with a caller during a transaction. Includes everything from "hello" to "goodbye."

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Using telecommunications to work from home or other locations instead of at the organization's premises.

Telephone Service Factor

See Service Level

Telephony Applications Programming Interface

CTI protocol developed by Microsoft and Intel.

Telephony Services Application Programming Interface

CTI protocol developed by Novell and AT + T.


The point at which an action, change or process takes place.

Tie line

A private circuit that connects two ACDs or PBXs across a wide area.

Traffic Control centre

See Network Control centre


See Call.

Transmission Control Protocol/Internet Protocol

The protocols that govern the exchange of sequential data. TCP/IP was designed by the U.S. Department of Defense to link dissimilar computers across many kinds of networks. It has since become a common standard for commercial equipment and applications.

True Calls Per Hour

Actual calls an individual or group handled divided by occupancy for that period of time.

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Also called a Line, Exchange Line or Circuit. A telephone circuit linking two switching systems.

Trunk Group

A collection of lines associated with a single peripheral and usually used for a common purpose.

Trunk Load

The load that lines carry. Includes both Delay and Talk Time.

Trunks Idle

The number of lines in a trunk group that are non-busy.

Trunks in Service

The number of trunks in the trunk group that are functional.

Unavailable Work State

An agent work state used to identify a mode not associated with handling telephone calls.

Uniform Call Distributor

A simple system that distributes calls to a group of agents and provides some reports. A UCD is not as sophisticated as an ACD.

Universal Agent

Refers to either A) An agent who can handle all types of incoming calls or B) An agent who can handle both inbound and outbound calls.

Virtual Call centre

A distributed call centre that acts as a single site for call handling and reporting purposes.

Visible Queue

When callers know how long the queue that they just entered is, and how fast it is moving (e.g., they hear a system announcement that relays the expected wait time). See Invisible Queue.

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Voice Processing

A blanket term that refers to any combination of voice processing technologies, including Voice Mail, Automated Attendant, Audiotex, Voice Response Unit (VRU) and Faxback.

Voice Response Unit

Also called Interactive Voice Response Unit (IVR) or Audio Response Unit (ARU). A VRU responds to caller entered digits or speech recognition in much the same way that a conventional computer responds to keystrokes or clicks of a mouse. When the VRU is integrated with database computers, callers can interact with databases to check current information (e.g., account balances) and complete transactions (e.g. make transfers between accounts). See Voice Processing.

Wide Area Network

The connection of multiple computers across a wide area, normally using digital data circuits.

Workforce Management Software

Software systems that, depending on available modules, forecast call load, calculate staff requirements, organize schedules and track real-time performance of individuals and groups.


Often used interchangeably with Call Load. Work load can also refer to non-call activities.

World Wide Web

The capability that enables users to access information on the internet in a graphical environment.

Wrap-Up Codes

Codes agents enter into the ACD to identify the types of calls they are handling. The ACD can then generate reports on call types, by handling time, time of day, etc.


See After-Call Work.

Zip Tone

See Beep Tone.

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List of Call Centre acronyms

ACD Automatic Call Distributor
ACS Automatic Call Sequencer 
ACW After Call Work 
AHT Average Handling Time 
ANI Automatic Number Identification
ARU Audio Response Unit 
ASA Average Speed of Answer 
ATA Average Time to Abandonment 
ATB All Trunks Busy 
BRI Basic Rate Interface 
CCR Customer Controlled Routing
CCS Centum Call Seconds 
CD-ROM Compact Disc - Read Only Memory
CED Caller Entered Digits 
CLI Calling Line Identity 
CO Central Office 
CPE Customer Premises Equipment
CSR Customer Sales or Service Representative
DN Dialed Number 
DNIS Dialed Number Identification Service
DRTV Direct Response Television
FX Foreign Exchange Line 
GOS Grade of Service 
IS Information Systems 
ISD Integrated Services Digital Network
IT Information Technology 
IVR Interactive Voice Response 
IXC Inter Exchange Carrier 
LAN Local Area Network 
LEC Local Exchange Carrier 
LED Light Emitting Diode 
MAC Moves, Adds and Changes 
MAN Metropolitan Area Network 
NCC Network Control centre 
NPA Numbering Plan Area 
OCR Optical Character Recognition
PABX Private Automatic Branch Exchange
PBX Private Branch Exchange 
PRI Primary Rate Interface 
PSTN Public Switched Telephone Network 
PUC Public Utility Commission 
RAN Recorded Announcement Route 
RFI Request for Information 
RFP Request for Proposal 
RSF Rostered Staff Factor 
TAPI Telephony Applications Programming Interface
TCP/IP Transmission Control Protocol/Internet Protocol
TSAPI Telephony Services Application Programming Interface
TSF Telephone Service Factor 
TSR Telephone Sales or Service Representative
UCD Uniform Call Distributor 
VRU Voice Response Unit 
WAN Wide Area Network 
WATS Wide Area Telecommunications Service
WWW World Wide Web