# Key Event Constants

This page describes the value that is passed to scripts in the `event` parameter. It is used in [Telemetry](/opentx-2-3-lua-reference-guide/part_i_-_script_type_overview/telemetry.md) and [One-Time](https://github.com/opentx/opentx-2-3-lua-reference-guide/tree/0d355d19f1961b689994cf78b84005864d33f9b5/one-time_scripts.md) scripts.

## The key event mechanism

Each time a key is pressed, held and released a number of events get generated. Here is a typical flow:

* when a key is pressed a `FIRST` event is generated
* if the key continues to be pressed, then after a while a `LONG` event is generated
* if the key continues to be pressed, then a `REPEAT` events are being generated
* when the key is released a `BREAK` event is generated

Couple of examples:

* a short press on key would generate: `FIRST`, `BREAK`
* a longer pres on key would generate: `FIRST`, `LONG`, `BREAK`
* even longer press: `FIRST`, `LONG`, `REPEAT,`REPEAT, ..., `BREAK`

This normal key event sequence can be altered with the [killEvents(key)](/opentx-2-3-lua-reference-guide/part_iii_-_opentx_lua_api_reference/general-functions-less-than-greater-than-luadoc-begin-general/killevents.md) function. Any time this function is called (after the `FIRST` event) all further key events for this key will be suppressed until the next key press of this key. Examples:

* kill immediately after the key press would generate: `FIRST`
* kill after the long key press would generate: `FIRST`, `LONG`

## Constants

The `event` parameter in the [Telemetry](/opentx-2-3-lua-reference-guide/part_i_-_script_type_overview/telemetry.md) and [One-Time](https://github.com/opentx/opentx-2-3-lua-reference-guide/tree/0d355d19f1961b689994cf78b84005864d33f9b5/one-time_scripts.md) scripts run function actually carries two pieces of information:

* key number
* type of event

The two fields are combined into one single number. Some of these combinations are defined as constants and are available to Lua scripts:

|   Key Event Name  |         Comments        |
| :---------------: | :---------------------: |
|  EVT\_MENU\_BREAK |   **MENU** key release  |
|  EVT\_PAGE\_BREAK |   **PAGE** key release  |
|  EVT\_PAGE\_LONG  | **MENU** key long press |
| EVT\_ENTER\_BREAK |   **ENT** key release   |
|  EVT\_ENTER\_LONG |  **ENT** key long press |
|  EVT\_EXIT\_BREAK |   **EXIT** key release  |
|  EVT\_PLUS\_BREAK |    **+** key release    |
| EVT\_MINUS\_BREAK |    **-** key release    |
|  EVT\_PLUS\_FIRST |     **+** key press     |
| EVT\_MINUS\_FIRST |     **-** key press     |
|  EVT\_PLUS\_REPT  |     **+** key repeat    |
|  EVT\_MINUS\_REPT |     **-** key repeat    |

Radios with rotary encoder (X7 and Horus) have also:

|  Key Event Name |           Comments           |
| :-------------: | :--------------------------: |
| EVT\_ROT\_BREAK |    rotary encoder release    |
|  EVT\_ROT\_LONG |   rotary encoder long press  |
|  EVT\_ROT\_LEFT |  rotary encoder rotated left |
| EVT\_ROT\_RIGHT | rotary encoder rotated right |

## Virtual events

Given the large number of radios supported by OpenTX, and the large difference in keys available on those, a set of VIRTUAL KEYS has been defined and are mapped to best fit available hardware

|    Virtual Key Event Name    |        Comments       |
| :--------------------------: | :-------------------: |
|   EVT\_VIRTUAL\_NEXT\_PAGE   |  for PAGE navigation  |
| EVT\_VIRTUAL\_PREVIOUS\_PAGE |  for PAGE navigation  |
|      EVT\_VIRTUAL\_ENTER     |                       |
|   EVT\_VIRTUAL\_ENTER\_LONG  |                       |
|      EVT\_VIRTUAL\_MENU      |                       |
|   EVT\_VIRTUAL\_MENU\_LONG   |                       |
|      EVT\_VIRTUAL\_NEXT      | for FIELDS navigation |
|   EVT\_VIRTUAL\_NEXT\_REPT   | for FIELDS navigation |
|    EVT\_VIRTUAL\_PREVIOUS    | for FIELDS navigation |
|   EVT\_VIRTUAL\_PREV\_REPT   | for FIELDS navigation |
|       EVT\_VIRTUAL\_INC      | for VALUES navigation |
|    EVT\_VIRTUAL\_INC\_REPT   | for VALUES navigation |
|       EVT\_VIRTUAL\_DEC      | for VALUES navigation |
|    EVT\_VIRTUAL\_DEC\_REPT   | for VALUES navigation |


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