But we don't have to go to so much trouble to make such an expensive long-distance call.
I used to make long-distance calls to the United States and Hong Kong, all of which were made with ip cards. The method of making domestic long-distance calls with ip is the same as making international long-distance calls. Domestic long distance is area code+telephone number, and international long distance is country code+telephone number.
The ip I use is very cheap. I bought a card of 100 and sold it of 16. Then, the call to the United States is 2.4 yuan/minute, and Hongkong is 1.5 yuan/minute. Plus the discount, it only takes 24 1 minute to call Hong Kong.
The cheapest way to make an international call by mobile phone is to find the ip calling card with the lowest discount.