I've recently bind my both R9 slim + OTA receiver on my quad, one for Telemetry ON and one for Telemetry OFF (Redundancy built).

In  CLI, I do make liked this,

set serialrx_halfduplex = OFF

set serialrx_inverted = OFF

get tlm

set tlm_halfduplex = OFF

set rssi_scale = 200

T18 Jumper settings

Bind

Ch 1 to 8 - Telemetry ON

Ch 1 to 8 - Telemetry OFF

Inputs

Set in Channel 9

Source = RSSI

Scale = 100 dB

Mixes

Set In channel 9

Offset = -100

Telemetry

Delete all sensors

Discover new sensors

Only appear with two lines but no more,

1. RxBt  4.9V  *

2. RSSI  100   *

Under Betaflight's Receiver Tab

Aux 12 - working

My Question Here

1. It appear my setup (Under Configuration Tab) just showing 20 to 21 % only, It also reflect the same when I view it under my FPV 

google. How to fix it?

2. Is that possible to bind as Ch 9 to 16 (Telemetry ON/OFF) since AUX 12 is working under this range ?

3. My Controller's Telemetry just shown two lines of result (RxBt, RSSI) after done with "delete & discover a new sensors", why?

What firmware are you using on the R9M slim? How is it wired to the FC?

FYI, It as ACCST Type of FLEX version. Both R9 slim + OTA also same with FLEX version of ACCST.

(Master)

SBUS OUT (serial) : RX1

S.PORT : TX2

VCC : +5 V

GND : Ground

SBUS IN (Master) : SBUS OUT (Slave)

(Slave)

VCC : +5 V

GND : Ground

Unless you have an F7 FC, you will need to wire the non-inverted S. Port (RX1 pin receiver ) to TX2 (FC).