When users develop some application programs required in highly real-time system on Windows OS, the problem of the bad hard real-time is usually nagging them. In order to solve this problem, IntervalZero provides an application development platform, RTX (Real Time eXtension), with a real-time runtime environment on Windows OS. As users install the RTX system on their PCs, it can take the highest execution priority from Windows OS. In order to satisfy the users to apply the RTX system, ICP DAS provides the RTX driver for PISO-CAN series CAN card. If users want to combine the CAN communication interface in their time-critical system, the RTX driver of the PISO-CAN series CAN cards can help them to do this easily and quickly. Furthermore, the name and parameters of the APIs in the RTX driver are the same as in the Windows driver. Users don’t need to pay more efforts to study how to use the APIs of the RTX driver if they have used the Windows driver before. The RTX driver increases the additional worth of the PISO-CAN series CAN cards, and satisfies the users to get the highly real-time system. By owing to the feature of high price performance and highly real-time, PISO-CAN series CAN cards will be applied in more wide and more variant CAN applications.