Tariffs are documents that are issued by various types of carriers that describe their voice and data services and the rates that are charged for each. These documents are filed with state and federal regulatory agencies and are accessible by the public, often over the Internet.

Tariffs that are filed at the FCC fall into three broad categories: dominant carriers, non-dominant carriers, and operator service providers. Dominant carriers include AT&T and the ILECs. Non-dominant carriers include MCI WorldCom and Sprint and various resale carriers who offer interstate long-distance services. CLECs also are considered by the FCC to be non-dominant carriers. Operator service providers offer long distance and, in some cases, local telephone services from public telephones, such as pay telephones or public telephones that are located in hotels/motels, hospitals, airports, restaurants, gas stations, convenience stores, and other public locations. These operators are not necessarily the same telephone companies that offer local service.

All carriers must still file tariffs for new services. Until recently, these tariffs had to be in effect for at least 30 days before the issuing carrier was permitted to revise the tariffs. This rule was originally intended to limit rate churn rapid rate increases and decreases in a short period. Rate churn can be disruptive or confusing for customers, making it difficult to determine what rates are applicable at any given time. Rate churn also makes it difficult for customers, especially businesses, to accurately budget telecommunications costs.