Calls may be inbound or outbound. Inbound calls are made by consumers, for example to obtain information, report a malfunction, or ask for help. In contrast, outbound calls are made by agents to consumers, usually for sales purposes (telemarketing). One can combine inbound and outbound campaigns.
Call center staff are often organised into a multi-tier support system for more efficient handling of calls. The first tier consists of operators, who initially answer calls and provide general information. If a caller requires more assistance, the call is forwarded to the second tier (in the appropriate department depending on the nature of the call). In some cases, there are three or more tiers of support staff. Typically the third tier of support is formed of product engineers/developers or highly skilled technical support staff for the product.
Telephone calls are easily monitored, and the close monitoring of call center staff is widespread. This has the benefit of helping the company to plan the workload and time of its agents.