Yealink SIP-T21 E2 User Manual page 170

User Guide for the SIP-T21(P) E2 IP Phone
3. Select the desired value (Optional or Compulsory) from the pull-down list of RTP
Encryption(SRTP).
4. Click Confirm to accept the change.
Note
SRTP is not available on all servers. Contact your system administrator for more
information.
SRTP is configurable via web user interface only.
How to export PCAP trace?
We may need you to provide a PCAP trace to help analyze your problem.
To export a PCAP trace via web user interface:
1. Click on Settings->Configuration.
2. Click Start to begin capturing signal traffic.
3. Recreate the error to be documented in the trace.
4. Click Stop to stop the capture.
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