Tenn. Code Ann. § 67-6-806: Agreement requirements

(a) The commissioner shall provide and maintain a database that describes boundary changes for all counties, cities and towns that levy a tax pursuant to part 7 of this chapter. This database shall include a description of the change and the effective date of the change for sales and use tax purposes.

(b) The commissioner shall provide and maintain a database of all sales and use tax rates for all counties, cities and towns of the jurisdictions that levy a tax pursuant to part 7 of this chapter. For the identification of the state, counties, cities and towns, codes corresponding to the rates must be provided according to Federal Information Processing Standards (FIPS) as developed by the National Institute of Standards and Technology.

(c) The commissioner shall provide and maintain a database that assigns each five-digit and nine-digit zip code within the state to the proper tax rates and jurisdictions. If the zip code area includes more than one (1) local tax rate, the rate assigned to that area shall be the lowest rate otherwise applicable within the area.

(d) The commissioner shall participate with other member states in the development of an address-based system for assigning taxing jurisdictions. The system shall meet the requirements developed pursuant to the federal Mobile Telecommunications Sourcing Act ( 4 U.S.C. § 119 ). If the commissioner develops an address-based assignment system pursuant to the Mobile Telecommunications Sourcing Act, a seller may use that system in place of the system provided for in subsection (c).