How it works
TLS secures SIP signalling hop by hop; audio confidentiality requires separately negotiated media protection such as SRTP. Protecting telephony and customer data combines technical controls, access rights and organisational processes. Different communication channels can require different safeguards.
Business example
A remote softphone protects registration and call-setup signalling when TLS is supported end to end.
What to consider
Review lawful data handling, key and access management, retention periods, audit trails and recovery procedures. No single mechanism replaces an overall security policy.