1. If the original phone is mobile, the database of used phone numbers will be in the mobile database. After the network switch, the database may not be migrated to Unicom network in time, and others may not be able to get through on the phone.

2. In the process of network transfer, the mobile phone number cannot be used normally.

3. If the SMS channel changes after changing operators, it is very likely that you will not receive SMS messages from BA card, WeChat and Alipay.

4. Because the signal coverage of operators is different in different regions, the signal after network transfer may be different from the original operators.

Extended data

Port number transfer has an impact:

1, and the communication charges have dropped.

After the implementation of port number transfer, operators with lower prices will win in the market with the same network quality. In order to compete for customers, operators will fight price wars to compete for users.

2. Operators pay more.

In order to reduce the impact of users leaving the network, operators have to pay more costs to improve their service capabilities. For example, the implementation of the port number transfer policy for four years has brought US mobile operators a cost of US$ 20 billion, and the maintenance cost alone exceeds US$ 500 million every year. In order to stabilize users, SKT spent 477.8 billion won in marketing expenses.

Number portability is applicable to:

1, the mobile users of China Telecom and China Unicom, and the mobile users of China Mobile Local Network except the users of TD special number segment 157/ 188, can carry numbers to other networks.

2. Mobile users of China Telecom and China Unicom can transfer their numbers to the TD-SCDMA network of China Mobile.

3. Users of China Mobile's TD-SCDMA special number segment 157/ 188 cannot carry it to other networks.

4. Users of virtual operator special number segment 170 cannot carry it to other operators' networks.