Yealink SIP-T48S User Manual page 139

Enter the desired delay time in the Hotline Delay field.
3.
The valid values range from 0 to 10 (seconds) and the default value is "4".
Tap the Save soft key to accept the change or
4.
Hotline is configurable via web user interface at the path Features->General Information.
Customizing Your Phone
to cancel.
129