Usable cable lengths are dependent upon data speed requirements, with speed/length combinations ranging from 200 kbps at 1200 meters to 12 Mbps at 100 meters. Using balanced differential signaling, RS-485 drivers send data across two output lines. The receiver determines the logic state by comparing the two signals; a difference greater than 200 mV provides a valid logic level. Differential amplifiers in the drivers and receivers steer current between the signal lines. This provides a high level of noise immunity in comparison with single-ended schemes such as RS-232.