A call centre or call center (see spelling differences) is a centralized office used for the purpose of receiving and transmitting a large volume of requests by telephone.
A call centre is operated by a company to administer incoming product support or information inquiries from consumers. Outgoing calls for telemarketing, clientele, and debt collection are also made. In addition to a call centre, collective handling of letters, faxes, and e-mails at one location is known as a contact centre.
A call centre is often operated through an extensive open workspace for call center agents, with work stations that include a computer for each agent, a telephone set/headset connected to a telecom switch, and one or more supervisor stations. It can be independently operated or networked with additional centres, often linked to a corporate computer network, including mainframes, microcomputers and LANs. Increasingly, the voice and data pathways into the centre are linked through a set of new technologies called computer telephony integration (CTI).
Most major businesses use call centres to interact with their customers. Examples include utility companies, mail order catalogue firms, and customer support for computer hardware and software. Some businesses even service internal functions through call centres. Examples of this include help desks and sales support. However, some companies employ staff to work in their call centres almost by "bulk", applicants requiring little or no educational qualifications or experience; an example is Lloyds TSB. In contrast, some firms demand lengthy customer service experience, various formal certificates and impose a complicated and staged recruitment interview procedure; an example of this is American Express.

Mathematical theory
The centralization of call management aims to improve a company's operations and reduce costs, while providing a standardized, streamlined, uniform service for consumers, making this approach ideal for large companies with extensive customer support needs. To accommodate for such a large customer base, large warehouses are often converted to office space to host all call centre operations under one roof.
Centralised offices mean that large numbers of workers can be managed and controlled by a relatively small number of managers and support staff. They are often supported by computer technology that manages, measures and monitors the performance and activities of the workers. Call centre staff are closely monitored for quality control, level of proficiency, and customer service. Typical contact centre operations focus on the discipline areas of workforce management, queue management, quality monitoring, and reporting. Reporting in a call centre can be further broken down into real time reporting and historical reporting. The types of information collected for a group of call centre agents typically include: agents logged in, agents ready to take calls, agents available to take calls, agents in wrap up mode, average call duration, average call duration including wrap-up time, longest duration agent available, longest duration call in queue, number of calls in queue, number of calls offered, number of calls abandoned, average speed to answer, average speed to abandoned and service level, calculated by the percentage of calls answered in under a certain time period.
Many Call Centres use workforce management software, which is software that uses historical information coupled with projected need to generate automated schedules. This aims to provide adequate staffing skilled enough to assist callers.
The relatively high cost of personnel and office space as well as need for large manpower and challenges around attrition, hiring and managing a large workforce influences outsourcing in the call centre industry.
Inadequate computer systems can mean staff take one or two seconds longer than necessary to process a transaction. This can often be quantified in staff cost terms. This is often used as a driving factor in any business case to justify a complete system upgrade or replacement. For several factors, including the efficiency of the call centres, the level of computer and telecom support that may be adequate for staff in a typical branch office may prove totally inadequate.

Accommodation
Call Centres use a wide variety of different technologies to allow them to manage the large volumes of work that need to be managed by the call centre. These technologies ensure that agents are kept as productive as possible, and that calls are queued and processed as quickly as possible, resulting in good levels of service.
These include ;

ACW (After call work)
ACD (automatic call distribution)
Agent performance analytics
Automated surveys
BTTC (best time to call)/ Outbound call optimization
IVR (interactive voice response)
CTI (computer telephony integration)
Enterprise Campaign Management
Outbound predictive dialer
CRM (customer relationship management)
CIM (customer interaction management) solutions (Also known as 'Unified' solutions)
Email Management
Chat and Web Collaboration
Desktop Scripting Solutions
Issue tracking system
Outsourcing
Third party verification
TTS (text to speech)
WFM (workforce management)
Virtual queuing
Voice analysis
Voice recognition
Voicemail
VoIP
Speech Analytics
Knowledge Management System
Electronic performance support systems Technology
There are a large number of patents covering various aspects of call centre technology. One of the early inventors in this field, Ronald A. Katz, personally holds over 50 seminal patents covering inventions related to toll free numbers, automated attendant, automated call distribution, voice response unit, computer telephone integration and speech recognition.. Mr. Katz has licensed his patents to over 100 companies including AT&T, IBM and Citibank, and has been characterized as a patent troll for his aggressive legal tactics.

Call centre dynamics
Many call centres have been built in areas that are depressed economically. This means that the companies get cheap land and labour, and can often benefit from grants to encourage them to improve employment in a given area.
China is investing in English language to make it an attractive location for outsourcing, and local demand as well as Japanese language skills in Dalian help its call center industry grow even without the English language capablilty.
India: A large number of call centres have moved to India, but further movement to India is on a decline as India rapidly absorbs most of the highly educated people in other outsourcing jobs and, like in other countries, call center jobs are increasingly viewed as stopgap jobs rather than as careers.
Mexico and Puerto Rico are destinations that help support the growing Latino population in the U.S. and are popular for Spanish language capability.
Pakistan is also an emerging market for Business Process Outsourcing and there is growth in call center business.
The Philippines, owing to its abundant English speakers that are college graduates and Americanized in English accent and cultural affinities. The Philippines was an American colony for almost 50 years.
Malaysia due to its multicultural composition and relatively cheap labour. British, Thai and Singaporean companies have reasonably large call centers here, especially in the field of banking, technology and aviation.
South Africa is emerging as a call centre location. Companies from countries including the United Kingdom, Germany, United States, the Netherlands, and France have outsourced call centre functions to South Africa. Factors such as relatively low labor costs, cultural affinity (with certain European and American target markets), good English and communication skills, and reliable infrastructure have contributed to this development.

Industry locations
Management of call centres involves balancing the requirements of cost effectiveness and service. Callers do not wish to wait in exorbitantly long queues until they can be helped and so management must provide sufficient staff and inbound capacity to ensure that the quality of service is maintained. However, staff costs generally form about 70% percent of the cost of running a call centre and so management must minimize the number of staff present.
To perform this balancing act, call centre managers make use of demand estimation, Telecommunication forecasting and dimensioning techniques to determine the level of staff required at any time. Managers must take into account staff tea and lunch breaks and must determine the number of agents required on duty at any one time.

Management of call centres
Forecasting results are vital in making management decisions in call centres. Forecasting methods rely on data acquired from various sources including historical data, trend data and so on. Forecasting methods must predict the traffic intensity within the call centre in quarter-hour increments and these results must be converted to staffing rosters. Special attention must be paid to the busy hour. Forecasting methods must be used to pre-empt a situation where equipment needs to be upgraded as traffic intensity has exceeded the maximum capacity of the call centre.

Forecasting demand
There are many standard traffic measurements (performance metrics) that can be performed on a call centre to determine its performance levels. However, the most important performance measures are:
These metrics give hard numbers on which to hang performance assessment. Quality Assurance can also be monitored by a quality assurance (QA) team, using call recording where the team manager listens to recorded calls and assesses performance of the agent, with coaching and training to help drive up performance.
Another way of measuring call centre performance is to use post-call IVR surveys to gain customer feedback. Customers are invited to take part in a short survey at the end of the call, where they can respond to pre-recorded questions by pressing the numbers on their telephone keypad or by speaking their comments.

The average delay a caller may experience whilst waiting in a queue
The mean conversation time, otherwise referred to as Average Talk Time (ATT)
The mean dealing time, otherwise referred to as Average Handling Time (AHT - equal to ATT plus wrap-up and/or hold time)
The percentage of calls answered within a determined time frame (referred to as a Service Level or SL%)
The number of calls / inquiries per hour an agent handles (CPH or IPH).
The amount of time spent while an agent processes customer requests while not speaking to a customer (referred to as Not Ready time/NR, or After Call Work/ACW, or Wrap-Up.)
The percentage of calls which completely resolve the customer's issue (if the customer does not call back about the same problem for a certain period of time, it is considered a successful resolution or FCR - First Call Resolution).
The percentage of calls where a customer hangs up or "abandons" the call is often referred to as Total Calls Abandoned or Percentage of calls abandoned. Calls are often abandoned due to long hold times when a call centre experiences a high call volume.
Percentage of time agents spend not ready to take calls, often referred to as Idle Time. Call centre performance
There are many refinements to the generic call centre model. Each refinement helps increase the efficiency of the call centre thereby allowing management to make better decisions involving economy and service.
The following list contains some examples of call centre refinements:

Predictive Dialling – Computer software attempts to predict the time taken for an agent to help a caller. The software begins dialling another caller before the agent has finished the previous call. This is because not every call will be connected (think of busy or not answered calls) and also because of the time it takes to set up the call (usually around 20 seconds before someone answers). Frequently, predictive dialers will dial more callers than there are agents, counting on the fact that not every line will be answered. When the line is answered and no agent is available, it is held in a retention queue for a short while. When still no agent has become available, the call is hung up and classified as a nuisance call. The next time the client is called an agent will be reserved for the caller.
Multi-Skilled Staff – In any call centre, there will be members of staff that will be more skilled in areas than others. An 'Interactive Voice Response' (IVR) Unit can be used to allow the caller to select the reason for his call. Management software, called an Automatic Call Distributor, must then be used to route calls to the appropriate agent. Alternatively, it has been found that a mix of general and specialist agent creates a good balance.
Prioritisation of Callers – Classification of callers according to priority is a very important refinement. Emergency calls or callers that are reattempting to contact a call centre are examples of callers that could be given a higher priority.
Automatic Number Identification – This allows agents to determine who is calling before they answer the call. Greeting a caller by name and obtaining his/her information in advance adds to the quality of service and helps decrease the conversation time. Refinements of call centres
There are many other issues that have to be planned for when managing a call centre. A few of these issues are listed below:

Call Center Noise Hazards
Planning for failure of equipment
Need for flexibility in meal-times and washroom needs
Need for job variety and training
Job exhaustion and stress
Staff turnover (high attrition rates are common in the call centre industry) Additional issues in call centres
The various components in a call centre discussed in the previous sections are the generic form of a call centre. There are many variations on the model developed above. A few of the variations are listed below:

Remote Agents – An alternative to housing all agents in a central facility is to use remote agents. These agents work from home and use a Basic Rate ISDN access line to communicate with a central computing platform. Remote agents are more cost effective as they don't have to travel to work, however the call centre must still cover the cost of the ISDN line. VOIP technology can also be used to remove the need for the ISDN, although the desktop application being used needs to be web enabled or VPN is used.
Temporary Agents – Temporary agents are useful as they can be called upon if demand increases more rapidly than planned. They are offered a certain number of quarter hours a month. They are paid for the amount they actually work, and the difference between the amount offered and the amount guaranteed is also paid. Managers must use forecasting methods to determine the number of hours offered so that the difference is minimised.
Virtual Call Centres – Virtual Call Centres are created using many smaller centres in different locations and connecting them to one another. The advantage of virtual call centres is that they improve service levels, provide emergency backup and enable extended operating hours over isolated call centres. There are two methods used to route traffic around call centres: pre-delivery and post-delivery. Pre-delivery involves using an external switch to route the calls to the appropriate centre and post-delivery enables call centres to route a call they've received to another call centre.
Interaction Centres – As call centres evolve and deal with more media than telephony alone, some have taken to the term, "interaction centre". Email, Web Callback, Chat and more are gradually being added to the role. Criticism of call centres
Unions in North America, including the United Steelworkers, have made some effort to gain members from this sector.