用串口模拟2个485读卡器，可模拟485地址和读到4字节卡号，方便门禁考勤程序的调试-485 simulation 2 with serial reader, can simulate 485 4-byte address and read the card number, to facilitate debugging of Access Control Program

模拟串口工具 可以自选串口参数 实现数据接收和发送。附带源码。(comtest :can send message and receive message ,with resource)