Add listen and isListen method
Add listen and isListen method

When you use another Software Serial, then you need to call this function so the SoftwareSerial gprsSerial can reveice data again. Because only one port Software Serial can active.
ImaduddinAMajid/GPRS_SIM900,ImaduddinAMajid/GPRS_SIM900,Seeed-Studio/GPRS_SIM900,Seeed-Studio/GPRS_SIM900