Phone call: "cellular -> USB modem -> SIP/VoIP phone -> cellular" - how to do?

Question

SIP

Good afternoon everyone! For a long time I want to implement an old idea. I often have to call in Russia to other cities and to numbers of different telecom operators. Sometimes I make calls abroad. Prices ~ 10 rubles per minute of conversation in Russia are not at all satisfied, not to mention calls abroad.

I use the services of Internet telephony of 2 operators: rynga and megaphone multiphone . For both, you need to have an Internet connection, but it is either not always available, or ... yes, in general, I have a simple phone, not a smart one, and if rynga still has a callback function to order a call through the opera mini, then the second one does not.

I would like to implement such a solution: I call the usb-modem computer, the modem picks up the phone, and then, listening to DTMF tones, dials the number of the called subscriber through some Internet telephony provider.

Question: how to implement something similar? I don't even know where to dig? Asterisk? If so, then again, where to dig?
Thanks

Answer 1

Since you use a multiphone, then everything is simple - install Asterisk. On it, without any USB modem (why?), connect the multiphone account (possibly separate) and the account of the SIP operator.
Then you call from your phone to the multiphone, and perform additional dialing.
In general, many SIP operators now have ready-made solutions for this - for example, sending an SMS with the phone number where we are calling, the operator already calls in both directions and connects.

Answer 2

google
first link

from there

Позвонил мне тут один хороший друг, и поинтересовался на тему организации CallBack на сервере Asterisk. Задача мне показалась весьма простой, и ее реализация, в моем понимании, должна занимать строчек 20 кода Немного погуглив и поигравшись с *, оказалось, что все проще чем кажется...

Huawei 3G modem works fine with asterisk.

Answer 3

FXO module for an asterisk - or an asterisk living on the correct router - description below) and a wifi handset / sip phone on a PC / on the Internet that connects to the router.
the router can be taken both on the basis of a PC, and a box, such as linksis / length, I don’t remember the model, I can try to ask the little man who had this.