Send USSD code to modem in C# and ERROR in return always

Question

I am sending USSD code on modem through serial port. But always it is giving ERROR in response.

AT commands I am sending are: in sequence:

serialPort.Wri         


        

Answer 1

Don't use \n in end of command, use only \r.

Form of CUSD command is: AT+CUSD=1,"*135#",15.

In C# it should be:

serialPort.Write("AT+CMGF=0" + "\r");
serialPort.Write("AT+CUSD=1,\"*135#\",15" + "\r");