China Telecom can't access the mobile network when making a phone call.

China Telecom telephone can't access the mobile network, which may be caused by signal coverage, data roaming settings and SIM card problems.

The mobile network signal may be unstable or not in your area. You can try to connect to the mobile network in different places or regions to see if there is any improvement.

Make sure that data roaming is enabled on your mobile phone. Sometimes, if data roaming is turned off, your mobile phone may not be able to connect to other operators' networks. In the settings of your phone, find the option of mobile network or data roaming and make sure it is turned on.

In order to ensure the normal operation of your SIM card, you can try to insert one SIM card into another mobile phone, or insert another SIM card into the mobile phone to rule out the possibility of SIM card failure.

Factors affecting cell phone signal

1. Distance to the base station: The distance between the mobile phone and the network base station is an important factor to determine the signal quality. The farther away from the base station, the signal strength may decrease, thus affecting the signal quality of mobile phones.

2. Obstacles: Obstacles such as buildings, mountains and trees will hinder the spread of signals. If there is an obstacle between the mobile phone and the base station, the signal may be weakened by interference.

3. Weather conditions: Extreme weather conditions, such as storms, thunder and lightning, may interfere with mobile phone signals, and heavy rain or heavy snow may cause signal weakening or interruption.