Abstract: The technologies for reducing electromagnetic radiation and improving the stability of ship-shore data communication is introduced. The serial ports on PCB（Printed Circuit Boards） and the SD card signal lines in the interested communication device is modeled and simulated to find the S parameters and the crosstalk phenomena of the signal lines. The electromagnetic coupling characteristics for different layouts are analyzed and the structure is redesigned. Reducing the diameter of vias and increase the width of signal lines are proved to be the effective measures to reduce the crosstalk of differential signal lines of PCB serial ports and improve the transmission efficiency of SD card signal lines.