How to send USSD request (via 3g modem) using C programming?

Question

Programming

How to send USSD request (via 3g modem) using C programming?

Answer 1

1st moment - the modem must create a virtual COM port for control through AT commands
2nd - under what OS is the application written?
If you need under Linux - then just open the device file corresponding to the 3G modem - i.e. COM port. And then write an AT command with a USSD request to this file.
If under Windows, use WinAPI or a third-party library to access the COM port and then write AT commands to it and parse responses.

Answer 2

Open modem documentation.
Open the port on which the modem is sitting.
Write there an AT command to initialize the modem and send a USSD request.
???
PROFIT
Since you ask such questions, it is better for you to google ready-made solutions.