Question:

“I require assistance with a mobile network issue. After entering the code `##4636##` into the dialer of my mother’s phone, I inadvertently altered the preferred network setting to ‘4G (LTE only)’, which has disabled the calling function. Although I’ve attempted to revert the settings to ‘4G/3G (LTE/GSM with PRL)’, the phone defaults back to ‘4G (LTE only)’ after each restart, which is often necessary due to frequent screen blackouts at maximum brightness. Could you provide guidance on permanently resolving the network setting to enable calling on 4G, and also suggest a solution to prevent the phone from hanging?”

Answer:

A common issue faced by smartphone users involves inadvertent changes to network settings that disrupt normal phone functionality. This article provides a solution to a problem where the network setting on a phone was changed to ‘4G (LTE only)’, resulting in disabled calling capabilities, and offers advice on how to prevent the phone from hanging due to screen blackouts.

Understanding the Issue:

The code `##4636##` is used to access the hidden Testing menu on Android phones, which allows for the alteration of network settings among other advanced options. Changing the network mode to ‘4G (LTE only)’ can indeed disable the ability to make or receive calls if the area does not support VoLTE (Voice over LTE) or if the phone’s firmware is not configured for it.

Step-by-Step Resolution:

1.

Access the Testing Menu:

– Dial `##4636##` to re-enter the Testing menu.

• Select ‘Phone Information’ to access network settings.

2.

Modify Network Settings:

• In the ‘Set preferred network type’ dropdown, choose an option that includes both LTE and GSM/WCDMA (auto connect) to allow the phone to switch between 4G for data and 3G/2G for calls.

3.

Persistent Setting:

• To ensure the setting persists after a restart, check if there’s an option to ‘Save’ or ‘Lock’ the settings within the Testing menu.
• If not, the issue might be with the phone’s firmware, and a software update or factory reset could be necessary.

Addressing the Screen Blackout Issue:

1.

Software Troubleshooting:

• Update the phone to the latest firmware version.
• Perform a soft reset by turning the phone off and on.

2.

Brightness Adjustment:

• Reduce the brightness to a lower level to see if the blackouts persist, as this could be a sign of a malfunctioning display at high brightness levels.

3.

Hardware Check:

• If the problem continues, it may indicate a hardware issue with the screen or other internal components, requiring professional repair.

Conclusion:

By following these steps, you should be able to restore the calling functionality on your mother’s phone and address the screen blackout issue. It’s always recommended to proceed with caution when dealing with advanced settings and to seek professional assistance if the problem persists or if you’re unsure of the steps. Remember, keeping the firmware up to date and understanding the implications of changing network settings are key to maintaining a smoothly functioning smartphone.