Yealink SIP-T48G Administrator's Manual page 514

Administrator's Guide for SIP-T2_Series_T4_Series IP Phones
server_certificates.url = http://192.168.1.20/ca.pem
Note: The certificate you want to upload must be in *.pem or *.cer format.
Web User Interface:
Security->Server Certificates->Load server cer file
Phone User Interface:
None
phone_setting.reserve_certs_enable
Description:
Enables or disables the IP phone to reserve custom certificates after it is reset to
factory defaults.
0-Disabled
1-Enabled
Web User Interface:
None
Phone User Interface:
None
To configure TLS on a per-line basis via web user interface:
1. Click on Account->Register.
2. Select the desired account from the pull-down list of Account.
3. Select TLS from the pull-down list of Transport.
4. Click Confirm to accept the change.
500
Parameters Permitted Values
0 or 1
Default
0