Enterprise IP Phone Using the Advanced Phone Functions
You can consult your system administrator for more information.
TLS
TLS(Transport Layer Security), an IETF standards track protocol (RFC 5246), was based
on the earlier SSL specifications developed by Netscape Corporation.
If you make a call based on TLS and SRTP (Set the transport as TLS and the SRTP as
On), the IP phone UI will display the connecting and ring back interface. If the reception
also set the transport as TLS, then IP Phone UI will display the icon on both side.
Go to Account->Basic, choose Transport option, in the pull-down menu, you can choose
the TLS option, and then click the Confirm button to save the change.