Eachine QX90 Frsky

Hello, i've got this quadcopter and bind it finally with my T8SG (Deviation 7)..!

But i don't understand how display battery voltage or other..!
I see that in FrSky protocol the "Telemetry" is on, then i go in Model Menu --> Telemetry and i try to set "Volt1 <= 4,70"
hope that if voltage is less then 4,70 display it... but nothing...
i then go in configuration page and set a box for Volt1 but always sign "0"..
Ehat is Volt1, Volt2 ecc..? Why only can set <= or >..?

What i must do to display always battery voltage for example..?

Thanks!

Receiver should output telemetry.
Frsky receiver of QX90 isn't.
It could be bad using Frsky receiver without telemetry or RSSI output.
Frsky protocol needs freq setting for reliable fly. It's unable to set precise freq without RSSI.
External frsky receiver on QX90 can output RSSI with moding.
If receiver integrated, maybe can't.

i don't known this..!
Thanks!