说明：  基于测试服务器实现有人GPRS730 DTU透传，连接到测试服务器；实现串口向测试服务器发送数据，服务器自动返回接收到的数据；
(Based on the test server, GPRS730 2G DTU is transmitted to the test server and connected to the test server. Serial port is used to send data to the test server, and the server automatically returns the received data.)