Yealink VC400 Administrator's Manual page 254

Administrator's Guide for Yealink Video Conferencing Systems
Select TLS from the pull-down list of the Transport.
2.
Click Confirm to accept the change.
3.
To upload a CA certificate via web user interface:
Click on Security->Trusted Certs.
1.
Click Browse to locate the certificate (*.pem,*.crt, *.cer or *.der) from your local system.
2.
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