Yealink SIP-T54S Administrator's Manual page 688

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/T5 Series/CP860/CP920 IP Phones
To configure the call pull feature access code via web user interface:
Click on Account->Advanced.
1.
Select the desired account from the pull-down list of Account.
2.
Enter the call pull feature access code (e.g., *11) in the Call Pull Feature Access Code
3.
field.
Click Confirm to accept the change.
4.
To configure the private hold soft key via web user interface:
Click on Settings->Softkey Layout.
1.
Select Enabled from the pull-down list of Custom Softkey.
2.
Select On Talk from the pull-down list of Call States.
3.
Select PriHold from the Unselected Softkeys column and then click
4.
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