To facilitate tax collection, some countries have laws requiring all sellers of goods and services to use cash register software that meets certain requirements. Tills equipped with such software are called fiscal cash registers. Requirements differ from country to country. Receipts issued by sellers may generally be required to contain a serial number for each transaction, seller's name, address and tax identification number, description sufficient to identify goods, quantity, tax rate, and price of goods, total amount of tax chargeable, etc. Fiscal cash register software may be required to communicate with the tax authority, reporting each transaction to prevent grey economy.