How to make a sip gsm gateway from usb modem Huawei E1550?

Question

VoIP

In general, the essence of the problem: there is a computer with windows and a huawei e1550 usb modem. You need a (preferably boxed) solution - you plug the modem into the computer, it gives sip settings so that I can call from my SIM card through a softphone in another country. I am not friends with linux and asteriks. Oktel sip-gsm can only be connected to an existing PBX (you need to enter the server ip), but I don’t have an PBX and I think this is a difficult path.

Answer 1

https://zadarma.com/ru/ - I tried to connect through it.
True, it seems like you have to pay 5 USD. for three months.