这是我从网看到的，不用电平的转换IC就可以把串口TTL输入、输出的电平转换成计算机能识别的电平，原图经测试不能用，经我改进后效果很好，大家不妨一试-This is what I see from the network, not power conversion IC level can be the serial TTL input and output level into the computer to identify the level, the maximum should not