G.Discrete MultiTone (G.DMT) modulation is an ITU global industry standard for the operation of full-rate ADSL at rates of up to 8 Mbps downstream and up to 640 Kbps upstream over telephone lines at a distance of up to 18,000 feet from the exchange. The American National Standards Institute (ANSI) has published a nearly identical industry standard (known as T1.413) for full-rate ADSL in the United States of America.