Yealink SIP-T2 SERIES Administrator's Manual page 928

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/CP860 IP Phones
2. Select Enabled from the pull-down list of Span to PC Port.
3. Click Confirm to accept the change.
A dialog box pops up to prompt that settings will take effect after a reboot.
4. Click OK to reboot the phone.
Then you can use Sniffer, Ethereal or Wireshark software to capture the signal traffic.
The IP phone provides a troubleshooting feature called ―Watch Dog‖, which helps you
monitor the IP phone status and provides the ability to get stack traces from the last time
the IP phone failed. If Watch Dog feature is enabled, the IP phone will automatically
reboot when it detects a fatal failure. This feature can be configured using the
configuration files or via web user interface.
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