Yealink SIP-T4X Administration Manual page 304

Example
Parameter-
features.busy_tone_delay
Description
Format
Default Value
Range
Example
Parameter-
features.normal_refuse_code
Description
Format
Default Value
Range
account.1.dnd.off_code = *74
Configuration File
<y0000000000xx>.cfg
Configures a period of time (in seconds) for
which the busy tone is audible on the IP phone.
When one party releases the call, a busy tone
is audible to the other party, indicating that the
call connection breaks.
If it is set to 3, a busy tone is audible for 3
seconds on the IP phone.
Integer
0
Valid values are:
0-0s
3-3s
5-5s
features.busy_tone_delay = 0
Configuration File
<y0000000000xx>.cfg
Configures a return code and reason of SIP
response messages when rejecting an
incoming call. A specific reason is displayed
on the caller's phone LCD screen.
If it is set to 486 (Busy here), the caller's LCD
screen will display the message "Busy here"
when the callee rejects the incoming call.
Integer
486
Valid values are:
404-No Found
480-Temporarily not available
Appendix
289