# Settings Page

## Aircraft

### Callsign

An alpha-numeric field with a maximum of 8 characters.\
The valid character values are the codes for the numbers '0' through '9', the letters 'A' through 'Z', and spaces.

### Pressurised Cabin

[According to ForeFlight](https://www.foreflight.com/connect/spec/) :

> Altitude is defined as ownship pressure altitude (referenced to 29.92 inches Hg).\
> For unpressurized aircraft a barometer in the cabin is close enough for practical purposes, but in pressurized aircraft, care must be taken to set this field to 0xFFF (Invalid or Unavailable) if the device does not have access to outside pressure.\
> Setting ownship pressure altitude incorrectly will result in incorrect calculation of relative traffic altitude.

If your device does not support atmospheric pressure (Barometer), this option is disabled, and set to true.\
This means that if your device does not have a barometer, you cannot send barometric altitude.

So, there are three options:

* No barometer on device, Altitude is sent as `Invalid`
* Barometer available, but pressurised cabin: Altitude sent as `Invalid`
* Barometer available, and unpressurised cabin: Altitude sent as actual pressure altitude.

## Preset Settings

Here you can select between two presets, **ForeFlight** and **Manual** modes.

### ForeFlight

This configures GPS4Flight to connect automatically to ForeFlight, as long as both devices are on the same network.\
This mode sets the network output mode to Unicast, and the listen port to 63093, as per ForeFlight requirements.

### Manual

This lets you change all network settings as you wish, for GDL90 requirements other than ForeFlight.

{% hint style="info" %}
When GPS4Flight is in **Manual** mode - there is no need for a **Listen Port**.\
That option is automatically removed in this mode.
{% endhint %}

## Network Configuration

Here you can specify the IP Network Settings.\
If you don't know what these setings mean, stay with `Unicast` to be safe.

By default, ForeFlight expects `Unicast` messages, and any device to listen on port 63093.

### Unicast / Broadcast

* `Unicast` is the 'normal' way of transmitting data from one device to one other.
* `Broadcast` transmits from one device to many possible devices simultaineously. Not all networks or devices support this mode.

### Listen Port

This is the port number that GPS4Flight will listen for ForeFlight 'heartbeat' messages. By default ForeFlight expects applications to listen on 63093.

### Destination Port

This is the port where GPS4Flight is sending its data.

* In `ForeFlight` mode, it will automatically be set when connected. (Default 4000).
* In `Manual` mode, you can send the data to any port you select.

### Destination Address

This is the address where GPS4Flight sends its data.

* In `ForeFlight` mode, it will automatically be set when connected.
* In `Manual` mode, you can send the data to any address on your network that you select.

## General

### Audible Error Alert

If there is an error or a warning, GPS4Flight can give a little audible notification.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://faq.gps4flight.capsicumdreams.com/settings.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.