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 centre 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
A call centre can be viewed, from an operational point of view, as a queueing network. The simplest call centre, consisting of a single type of customers and statistically-identical servers, can be viewed as a single-queue. Queueing theory is a branch of mathematics in which models of such queueing systems have been developed. These models, in turn, are used to support work force planning and management, for example by helping answer the following common staffing-question: given a service-level, as determined by management, what is 
the least number of telephone agents that is required to achieve it. (Prevalent examples of service levels are: at least 80% of the callers are answered within 20 seconds; or, no more than 3% of the customers hang-up, due to their impatience, before being served.)
Queueing models also provide qualitative insight, for example identifying the circumstances under which economies of scale prevail, namely that a single large call centre is more effective at answering calls than several (distributed) smaller ones; or that cross-selling is beneficial; or that a call centre should be quality-driven or efficiency-driven or, most likely, both Quality and Efficiency Driven (abbreviated to QED). Recently, queueing models have also been used for planning and operating skills-based-routing of calls within a call centre, which entails the analysis of systems with multi-type customers and multi-skilled agents.
Call centre operations have been supported by mathematical models beyond queueing, with operations research, which considers a wide range of optimisation problems, being very relevant. For example, for forecasting of calls, for determining shift-structures, and even for analysing customers' impatience while waiting to be served by an agent.
Accommodation
The centralisation of call management aims to improve a company's operations and reduce costs, while providing a standardised, 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.
Call centre dynamics
Types of calls are often divided into outbound and inbound. Inbound calls are calls that are made by the consumer to obtain information, report a malfunction, or ask for help. These calls are substantially different from outbound calls, where agents place calls to potential customers mostly with intentions of selling or service to the individual. (See telemarketing)
Call centre staff are often organised into a multi-tier support system for a more efficient handling of calls. The first tier in such a model consists of operators, who direct inquiries to the appropriate department and provide general directory information. If a caller requires more assistance, the call is forwarded to the second tier, where most issues can be re
solved. In some cases, there may be three or more tiers of support staff. If a caller requires more assistance, the caller is forwarded to the third tier of support; typically the third tier of support is formed by product engineers/developers or highly skilled technical support staff of the product.
Call centres have their critics. Some critics argue that the work atmosphere in such an environment is de-humanising. Others point to the low rates of pay and restrictive working practices of some employers. There has been much controversy over such things as restricting the amount of time that an employee can spend in the toilet. Furthermore, call centres have been the subject of complaints by callers who find the staff often do not have enough skill or authority to resolve problems, while the dehumanised workers very often exhibit an attitude of apathy to even the most abusive customer.
Owing to the highly technological nature of the operations in such offices, the close monitoring of staff activities is easy and widespread. This can be argued to be beneficial, to enable the company to better plan the workload and time of its employees. Some people have argued that such close monitoring breaches human rights to privacy. Yet another argument is that close monitoring and measurement by quantitative metrics can be counter-productive in that it can lead to poor customer service and a poor image of the company.
