How to prevent crosstalk in HMIs with multiple communication interfaces?

To prevent crosstalk between multiple communication interfaces within an HMI, isolation design is required in layout, routing, and power supply. First, PCB layout should be partitioned, separating different types of communication interface circuits, such as RS485, CAN, Ethernet, and USB, using ground or power planes as isolation bands, or physically separating them. During routing, long parallel runs of signal lines from different interfaces, especially clock and data lines, are strictly prohibited. If close proximity is unavoidable, sufficient spacing should be ensured, and ground lines should be added for isolation. Each interface's transceiver should be provided with independent power filtering, i.e., powered separately from the common power supply via a ferrite bead or LDO, for example, using a PBZ1608 series ferrite bead for isolation, to avoid noise coupling through the power path. The ground plane of each interface circuit can be physically separated and connected to the digital main ground at a single point via a ferrite bead or a 0Ω resistor. For high-speed interfaces, such as Ethernet and USB, their differential correspondences should be strictly routed according to regulations and properly grounded. Shielded connectors should be used, and the shields should be connected to the independent ground of their respective interface areas. By strictly dividing the area, isolating the power supply, and standardizing the wiring, and by using isolation devices such as ferrite beads from Eternity, crosstalk between multiple communication interfaces within the HMI can be minimized.