# OMP

## Details

**Protocol Number:**  77\
**Autobind:**  No\
**Channel Re-mapping:**  Yes\
**Extended Limits:**  No\
**Failsafe Support:**  No\
**Receiver Match:**  Yes\
**Telemetry:**  No\
**Option Value:**  Emulation mode and frequency fine tuning (see notes)\
**Firmware Version:** v1.3.1.59

## Notes

{% hint style="warning" %}
This protocol is known to be problematic.  This is due to the emulation of the original radio's RF component.
{% endhint %}

If the model does not respond well to inputs, or is hard to bind, you can try to switch the emulation mode by using an option value (RF Freq. tuning) other than 0.

Once the value is not set to 0 it is used for frequency fine tuning.  See the [Frequency Tuning page](/using-the-module/frequency-tuning.md) for more details.

Telemetry is supported only if a NRF24L01 RF component is installed:

* A1 = battery voltage including "recovered" battery voltage from corrupted telemetry packets
* A2 = battery voltage from only good telemetry packets
* RX\_RSSI = TQly = percentage of received telemetry packets (good and corrupted) from the model which has nothing to do with how well the RX is receiving the TX

How to calculate accurately the OpenTX Ratio and Offset: 

* Set the Ratio to 12.7 and Offset to 0
* Plug in two  batteries with extreme voltage values
* Write down the values Batt1=12.5V & Telem1=12.2V, Batt2=7V & Telem2=6.6V 
  * Ratio=12.7\*\[(12.5-7)/(12.2-6.6)]=12.47 => 12.5 
  * Offset=12.5-12.2\*\[(12.5-7)/(12.2-6.6)]=0.517 => 0.5

**Models:** OMP HobbyM1 & M2 Helicopters, T720 RC Glider

## Channel Assignment

| CH1 | CH2 | CH3        | CH4 | CH5       | CH6  | CH7  |
| --- | --- | ---------- | --- | --------- | ---- | ---- |
| A   | E   | Thr. Pitch | R   | Thr. Hold | Idle | Mode |

**Idle:**  -100% = Beginner Mode; 0% = Idle 1; +100% = Idle 2\
**Mode:**  -100% Attitude(?); 0% Attitude; +100% 3D\
**M2 Mode:**  -100% 6G; 0% 3D; +100% 3D


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