Referring to the ability of a device, such as a modem, to dynamically adjust the speed of data transfer to varying line conditions in order to ensure the integrity of the datastream.The actual transmission speeds that modems can realize in either direction depends on the attributes of the analog local loop and various transient interference issues. Modem speeds are stated in terms of their maximums, based on the assumption that conditions are optimal. When modems initially connect, they negotiate a transmission rate based on their individual capabilities and their common evaluation of the quality of the connection. Should the quality of the connection deteriorate, dynamic rate adaptation enables fallback modems to negotiate a lower rate of transmission, using a less sophisticated modulation technique and perhaps adjusting the baud rate, and to ratchet up the transmission rate when conditions improve. See also baud rate, modem, modulation, signaling rate, and transmission rate.