Troubleshoot the phone sound quality

When you encounter the sound quality problem while using the phone, please do the following troubleshooting:
1. Try to change the curve of the phone handset of both the caller and called parties and then test again.

2. Check if the connection between the phone handset and the curve of both the caller and called parties is normal.

3. The sound quality problem occurs during the call, immediately switch from the handset mode to the speaker mode or switch from the speaker mode to the handset mode to check whether there is a problem with the sound quality.