目前在工业控制领域,单片机系统主要通过RS232、RS485和CAN总线协议通信,它们无法直接与互联网连接,因此该系统处于与互联网隔绝的状态。这些系统广泛采用低成本8位单片机,而这种单片机一般只具有RS232异步串行通信接口,要接入到互联网必须进行通信接口改造,这种改造不仅是接口的物理改造,更关键是数据格式的改造和通信协议的转换。本文提出一种RS232串行通信接口与RJ45以太网接口转换器的设计方案,已有的单片机系统可以通过该转换器接入到以太网,进一步接入互联网。-Currently in the field of industrial control, single-chip microcomputer system mainly through RS232, RS485 and CAN bus protocol communications, they can not be directly connected to the Internet, so the system is in a state of isolation and the Internet. These systems are widely used in low-cost 8-bit MCU, which generally has a single-chip RS232 asynchronous serial communication interface, to access to the Internet must be communication interface transformation, such transformation is not only the physical interface transformation, more crucial is the transformation of data format and communication protocol conversion. In this paper, a RS232 serial communication interface with RJ45 Ethernet interface converter design, the existing single-chip microcomputer system via the access to Ethernet converter, and further access to the Internet.