A call center is a central office where all telephonic calls are received and transmitted. A call center is operated by a company to supervise incoming product support or informative queries from customers. The staff of telemarketing also administers outgoing calls which are made for clients and debt collection. Some staff members also handle the letters, faxes and emails and this official section is known as contact center. The call centers are mostly operated through a workstation where all call center agents have their own computer, telephone set/head set, linked to a telecom switch board and supervising station. It can be operated autonomously or connected with additional call centers, particularly having corporate computer networks, macro-frames or micro-frames and LANs. Moreover computer telephony integration (CTI) technologies are applied for transmission of voice and data pathways into a call center. A large number of business corporations offer telemarketing services to interact with their potential clients e.g. utility companies, customer assistance for computer hardware/software and mail order catalogue firms etc.