Snom m9 DECT Administrator's Manual page 31

Security
Secure call status is indicated on the snom m9 handset. If the phone successfully registered a TLS/SRTP ses-
sion, the closed padlock icon will be displayed.
Certificate Authority Setup
Custom configured CAs can be viewed by clicking Status > Network > Root Certificate Authorities from
the snom m9 web interface. (Additional CAs can be added, but you cannot delete select CAs. However, doing
a factory reset from the base will clear all the configured CAs.)
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