CAN(Controller Area Network) is a serial communication protocol with a very high level of security. It is an especially suit to distributed real-time system control and monitor, such as industrial machine control, aircraft engines, factory automation, medical equipment, building automation, remote data acquisition and control, environment monitor…etc. In order to use high performance CAN bus with WinCon and Lincon series main control unit of ICP DAS, we provide a CAN bus expansion slot module, I-8KCAN. The difference between the I-8KCAN and I-87KCAN are the communication methods. I-87KCAN is proper for low bus loading. The I-8KCAN use DPRAM to communicate with main control unit and can give high performance in sending and receiving CAN messages. On WinCE platform of WinCon series main control unit, the EVC++ library is given for programming users’ CAN application. We also provide the GCC library for LinCon users to develop the CAN application. Therefore, I-8KCAN help users not only to build their CAN system, but also to structure a CAN network with ICP DAS CAN-related products and the CAN products from other companies. The general application architecture is depicted as the following figure :