Yealink SIP-T2xP Auto Provisioning Manual page 203

Parameter
phone_setting.mute_power_led_flash_enable =
(not applicable to CP860 IP phones)
Permitted Values
The default value is 0.
For SIP-T4X IP phones:
0-Disabled (power indicator LED does not
flash)
1-Enabled (power indicator LED slow
flashes (1000ms) red)
The default value is 1.
If it is set to 0, the status of the power
indicator LED is determined by the value of
the parameter
"phone_setting.common_power_led_enabl
e".
It enables or disables the power indicator
LED to flash when a call is mute.
For SIP-T2xP/T19P IP phones:
0-Disabled (power indicator LED does not
flash)
0 or 1
1-Enabled (power indicator LED fast flashes
(300ms) green)
The default value is 1.
For SIP-T4X IP phones:
Descriptions
Features->Power LED->Mute Power
Light On
Appendix
Web Setting Path
193