The Data and Address bus contain many lines that switch on and off simultaneously. This constant switching causes instantaneous large currents to flow through the GND and power supply lines resulting in unwanted noise. Therefore, it is necessary to suppress the current flow on the signal linen. The BLM Series (Chip Ferrite Bead) is generally used for this purpose. On the control bus line, especially at high operating speeds, the BLMxxB Series (Chip Ferrite Bead for high-speed signal lines that features a steep impedance rising) is used. On bus lines with high-level noise, the NFR21G series (Chip "EMIFIL®") may be effective.

The radiation spectrum of noise generated from bus lines resembles that of noise generated from the motor. It is important to check which of the motor or bus lines is the source of the noise and then install EMI filters.