使用C在Linux中通过串口读取来自sim的SMS消息

am trying to read sms messages via serial port in linux a from a sim card which i have placed inside a huawei 3g usb modem. i have to execute the script a number of time before some of the sms messages are displayed on the screen. At times it displays unusual characters. All i want to do is read sms messages from the sim using AT commands, c and serial port. Below is the code i am using.am trying to read sms messages via serial port