Yealink SIP-T48G Administrator's Manual page 235

To configure the server certificates via web user interface:
1. Click on Security->Server Certificates.
2. Select the desired value from the pull-down list of Device Certificates.
3. Click Confirm to accept the change.
To upload a server certificate via web user interface:
1. Click on Security->Server Certificates.
2. Click Browse to select the certificate (*.pem and *.cer) from your local system.
3. Click Upload to upload the certificate.
A dialog box pops up to prompt "Success: The Server Certificate has been loaded!
Rebooting, please wait...".
Configuring Security Features
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