Traditionally, a call center is defined as a physical location where calls are placed, or received, in high volumes. This could be for the purpose of sales, marketing, telemarketing, customer service, technical support or specialized business activity.

Call centers are also described as "customer care centers", "contact centers", "multimedia access centers" and "service bureaus". A multimedia call center encompasses Internet web sites and electronic commerce, in addition to phones.

A call center could be one or all of these - a huge telemarketing center, a tele-servicing center, a help desk, a service bureau that uses its large capacity to serve lots of companies, a reservation center for airlines or hotels, a catalog retailer, an e-tailing center, an e-commerce transaction center, or even a fund-raising and collection organization.