c# - Dialing a network service number like #100*3# by AT Command

Question

How to dial a network service number like #100*3# by AT Command? And what is the correct syntax in C# because when I try to dial it, the application considers it as a phone number and I hear a message that means that I can't dial this number.

Note: the code is successfully running and I can successfully dial any phone number but the problem is in the network service numbers.

I tried the following code:

sp.WriteLine("AT+CUSD=1,#"+100+"*3#,15"+Environment.NewLine );

Answer 1

The correct syntax for the AT+CUSD command is specified in 27.007:

AT+CUSD=[<n>[,<str>[,<dcs>]]]

and the <str> parameter is a string which must be enclosed in double quotes. From V.250:

String constants shall be bounded at the beginning and end by the double-quote character

So your code should be

sp.WriteLine("AT+CUSD=1,\"#100*3#\",15\r");

Update: You should never use Environment.NewLine to terminate the command line, it should just be \r always.