Auto-dialing of CSD sim-cards via GSM modem. How to write a script?

Question

Programming

Greetings! The following task has emerged.
There is a principle of interaction [program <=> modem <=> modem <=> device]
Ie . the program starts sending AT commands to the interface port of the modem, the modem, in turn, from its SIM card, makes a voice call to the phone number of the SIM card installed in another modem.
The remote modem answers the call.
This creates a communication channel between the two modems through which we can send or receive any data.
It is necessary for the program to automatically call the list of numbers, and if it was not possible to reach a certain number, output information about this to another file.
Maybe someone will share a ready-made solution or help with the implementation (possibly for a fee).

Answer 1

I will not share implementation, I will share advice.
Please note that the CSD data service may be disabled on the SIM and will need to be enabled separately.

Answer 2

Try asterix or any other telephony.
https://habr.com/en/post/159503/

Answer 3

1. Open the serial port.
2. Give the necessary commands.
3. Scan the result.
4. If there is an error, then output it to another file.
5. Repeat p2.