Yealink SIP-T54S Administrator's Manual page 605

Parameter
Applications) feature on the IP phone.
0-Disabled
1-Enabled
Note: It is not applicable to SIP-T19(P) E2/CP860 IP phones. If you change this parameter,
the IP phone will reboot to make the change take effect.
Web User Interface:
Features->Remote Control->CSTA Control
Phone User Interface:
None
To configure uaCSTA feature via web user interface:
Click on Features->Remote Control.
1.
Select the desired value from the pull-down list of the CSTA Control.
2.
Click Confirm to accept the change.
3.
A dialog box pops up to prompt that the settings will take effect after a reboot.
Click OK to reboot the phone.
4.
Configuring Basic Features
Permitted Values Default
579