The RSSI is the upper pin.

Calibration
Please enter into OSD Menu
OSD->Calibrate->RSSI
1. Select RSSI by Switch(Channel 3)
2. Switch(Channel 4) up or down, the RSSI value will blink.
3. Make you RSSI value, max and min
4. Switch(Channel 4) up or down, the RSSI value will stop blink and save the value
5. Switch(Channel 3) up or down, return the flying mode.

No change the value by your hand.
Just keep the RC control power ON / Off
Or
Keeps RC control near / away from RC receiver
The OSD will detect the MAX and MIN value automatically.
Disconnect RSSI pin from OSD
Replace
Turn off the RC power
Please enter into OSD Menu
OSD->Calibrate->RSSI
1. Select RSSI by Switch(Channel 3)
2. Switch(Channel 4) up or down, the RSSI value will blink.
3. Connect/Disconnect RSSI pin with OSD, the OSD will detect the MAX and MIN(0) value automatically.
4. Switch(Channel 4) up or down, the RSSI value will stop blink and save the value
5. Switch(Channel 3) up or down, return the flying mode.
Calibration
Please enter into OSD Menu
OSD->Calibrate->RSSI
1. Select RSSI by Switch(Channel 3)
2. Switch(Channel 4) up or down, the RSSI value will blink.
3. Make you RSSI value, max and min
4. Switch(Channel 4) up or down, the RSSI value will stop blink and save the value
5. Switch(Channel 3) up or down, return the flying mode.
No change the value by your hand.
Just keep the RC control power ON / Off
Or
Keeps RC control near / away from RC receiver
The OSD will detect the MAX and MIN value automatically.
Disconnect RSSI pin from OSD
Replace
Turn off the RC power
Please enter into OSD Menu
OSD->Calibrate->RSSI
1. Select RSSI by Switch(Channel 3)
2. Switch(Channel 4) up or down, the RSSI value will blink.
3. Connect/Disconnect RSSI pin with OSD, the OSD will detect the MAX and MIN(0) value automatically.
4. Switch(Channel 4) up or down, the RSSI value will stop blink and save the value
5. Switch(Channel 3) up or down, return the flying mode.