Dialing in the same city is the local telephone charge; In different places, there are long-distance charges.
In addition, 800 telephone is free, but it can only be dialed by fixed telephone or PHS, and the mobile phone cannot dial;
400 calls can be made by mobile phone, but only free of long-distance charges; In other words, whether you make a phone call in your local city or in a different place, you have to charge a local phone bill.