对IEC104通讯机制进一步说明，从报文到原理，说明详尽，很好的一份资料(The communication mechanism of IEC104 is further explained, from message to principle, which is a detailed and good data)

iec104通信规约解析，中文简洁概述，通俗易解，适合新手(IEC 104 communication protocol analysis, Chinese concise overview, easy to understand, suitable for novices)