Yealink SIP-T21 E2

Administrator’s Guide for SIP-T2 Series/T19(P) E2/T4 Series/T5 Series/CP860/CP920 IP Phones
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SIP server and outbound proxy server. It can prevent the phone receiving ghost calls from
random numbers like 100, 1000, etc. To stop this from happening, you also need to disable
allow IP call feature. For more information on allow IP call, refer to Allow IP Call on page 394.
Procedure
Accept SIP trust server only can be configured using the following methods.
Central Provisioning
(Configuration File)
<y0000000000xx>.cfg
Configure accept SIP trust server only.
Parameter:
sip.trust_ctrl
Web User Interface
Configure accept SIP trust server only.
Navigate to:
http://<phoneIPAddress>/servlet?p=fe
atures-general&q=load
Details of Configuration Parameter:
Parameter
Permitted Values
Default
sip.trust_ctrl
0 or 1
0
Description:
Enables or disables the IP phone to only accept the SIP message from the SIP server and
outbound proxy server.
0-Disabled
1-Enabled
Web User Interface:
Features->General Information->Accept SIP Trust Server Only
Phone User Interface:
None
To configure accept SIP trust server only feature via web user interface:
1. Click on Features->General Information.