智能232转485原代码，1个232进4个485出，上位机选者端口（C51），需要有KEIL 软件开发.-232 to 485 Intelligent original code, a 232 into four 485. PC elections were port (C51), the need for KEIL software development.

485通讯协议,用C51语言编写的,很详细的.-485 communications agreement with C51 language, and very detailed.

485开发说明，包含原理、芯片、接口电电路、原理图与MODBUS部分C51源代码 -485 development, including the principle of chip interface electrical circuit schematic and MODBUS part of the C51 source code