Microprocessor techniques are always developed with the purpose of achieving greater data capacity per unit time. There are many different types of cables on the market which can be used in connecting the digital processing system. No matter what kind of material the cable is made of, the characteristic impedance mismatch and crosstalk from the neighboring lines could generate the noise to the line itself. Therefore, it is necessary to reduce the noise, especially for the high frequency data transmission bus. This report presents a simulation of two long distance transmission buses and reducing the noise by diode terminators.