Yealink SIP-T2xP Auto Provisioning Manual page 201

Parameter
phone_setting.ring_power_led_flash_enable =
(not applicable to CP860 IP phones)
Permitted Values
0-Disabled (power indicator LED is off)
1-Enabled (power indicator LED is solid
green)
The default value is 1.
For SIP-T4X IP phones:
0-Disabled (power indicator LED is off)
1-Enabled (power indicator LED is solid red)
The default value is 0.
Note: The old parameter
"features.power_led_on" is also applicable
to IP phones and
"features.idle_talk_power_led_flash_enable
" is also applicable to SIP-T21P/T19P/T4X IP
phones.
It enables or disables the power indicator
LED to flash when the phone receives an
incoming call.
0 or 1 For SIP-T2xP/T19P IP phones:
0-Disabled (power indicator LED does not
flash)
1-Enabled (power indicator LED fast flashes
Descriptions
Features->Power LED->Ring Power
Light Flash
Appendix
Web Setting Path
191