【摘要】 公路电子收费系统中涉及多种通信技术，包括现场总线、局域网络和远程通信，本文介绍了基于智能通信卡的星型现场总线网以及基于ETHERNET的NETDDE在系统中的实现，并针对通信的实时性和可靠性提出了相应的解决方法，设计和应用实践证明，文中的方法满足了电子收费系统中的通信要求，具有很好实用性。更多还原

【Abstract】 Multiple technologies are used in Highway Toll System,including Fieldbus, LAN and remotecommunication. In this paper, we introduce two of them: the implementation of star - topologyfieldbus based on intelligent communication card and NETDDE based on ETHERNET. Considering of real-time performance and dependability,we present relatively strategies described as follow. Practice shows that these methods match the requirement of Toll system properly and practically.更多还原