The Mexican Statutory Standard (NOM) stipulates that imported products can be sold on the market only after passing the test. Although the "North American Free Trade Agreement" came into force on January 1, 1994, and Mexico's National Institute of Standardization and Certification of Electronics, in cooperation with UL and the Canadian Standards Association (CSA) issued a North American coordination standard, Mexico only recognizes itself. NOM safety signs, safety signs in the United States and Canada (eg CUL, ETL, CSA) are not recognized by the government. Product testing visas must be issued by Mexican Deccion General de Normas (DGN) or other accredited independent visa agency. Before the product can be imported, it must be approved by the visa to enter the country.