When making a domestic call in Chinese mainland, you should dial the toll number 0. However, when calling Chinese mainland from overseas (including Hongkong and Macau), you don't need to dial the long-distance crown code 0. For example, if you want to make an IDD call from the United States to Beijing, China, instead of using the switchboard, you should dial the American international crown code 0 1 1, China international area code 86, Beijing area code 10, and the telephone number. In Chinese mainland, if you want to make an international call (including Hong Kong, Macao and Taiwan), you need to add the international crown code "00" first, then add the international area code and the user's telephone number before you can get through.