meshtastic/docs/configuration/device-config/channels.mdx
2023-03-28 11:32:19 +02:00

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---
id: channels
title: Channel Configuration
slug: /settings/config/channels
sidebar_label: Channels
---
import Tabs from "@theme/Tabs";
import TabItem from "@theme/TabItem";
The Channels config options are: Index, Roles, and Settings. Channel config uses an admin message sending a `Channel` protobuf which also consists of a `ChannelSettings` protobuf.
:::info
**Channel Settings** (as described on this page) should not be confused with [Modem Preset Settings](/docs/settings/config/lora#modem-preset)
[Modem Preset Settings](/docs/settings/config/lora#modem-preset) contain the modem configuration (frequency settings, spreading factor, bandwidth, etc.) used for the LoRa radio. These settings are identical for all channels and can **not** be unique per channel.
**Channel Settings** contain information for segregating message groups, configuring optional encryption, and enabling or disabling messaging over internet gateways. These settings **are** unique and configurable per channel.
:::
## Channel Config Values
### Index
The channel index begins at 0 and ends at 7.
_Indexing_ can not be modified.
| Index | Channel | Default Role | Purpose |
| :---: | :-----: | :----------: | :-----------------------: |
| 0 | 1 | `PRIMARY` | Used as `default` channel |
| 1 | 2 | `DISABLED` | User defined |
| 2 | 3 | `DISABLED` | User defined |
| 3 | 4 | `DISABLED` | User defined |
| 4 | 5 | `DISABLED` | User defined |
| 5 | 6 | `DISABLED` | User defined |
| 6 | 7 | `DISABLED` | User defined |
| 7 | 8 | `DISABLED` | User defined |
:::note
You can **not** have `DISABLED` channels in-between active channels such as `PRIMARY` and `SECONDARY`. Active channels must be consecutive.
:::
### Role
Each channel is assigned one of 3 roles:
1. `PRIMARY` or `1`
- This is the first channel that is created for you on initial setup.
- Only one primary channel can exist and can not be disabled.
- Direct messages are only available on this channel.
2. `SECONDARY` or `2`
- Can modify the encryption key (PSK).
3. `DISABLED` or `0`
- The channel is no longer available for use.
- The channel settings are set to default.
:::note
While you can have a different PRIMARY channel and communicate over SECONDARY channels with the same PSK, a hash of the PRIMARY channel's name sets the LoRa channel number, which determines the actual frequency you are transmitting on in the band.
To ensure devices with different PRIMARY channel name transmit on the same frequency, you must explicitly set the LoRa channel number.
:::
## Channel Settings Values
The Channel Settings options are: ID, Name, PSK, Downlink Enabled, and Uplink Enabled. Channel settings are embedded in the `Channel` protobuf as a `ChannelSettings` protobuf and sent as an admin message.
:::note
The full globally unique ID will be constructed from the Name and ID (`<name>.<id>`) where ID is base36 encoded. Assuming that the number of Meshtastic users is below 20K (true for a long time) the chance of this 64 bit random number colliding with anyone else is super low. The penalty for collision is low as well.
:::
### ID
Used to construct a globally unique channel ID.
Set to `0` by default.
### Name
A short identifier for the channel. _(< 12 bytes)_
| Reserved Name | Purpose |
| :------------: | :----------------------------------------------------------------------------------------------------------------------------: |
| `""` (default) | If left empty on the Primary channel, this designates the `default` channel. |
| `admin` | On Secondary channels, the name `admin` (case sensitive) designates the `admin` channel used to administer nodes over the mesh |
### PSK
The encryption key used for private channels.
Hex byte `0x01` for the Primary `default` channel.
Must be either 0 bytes (no crypto), 16 bytes (AES128), or 32 bytes (AES256).
### Downlink Enabled
If enabled, messages captured from a **public** internet gateway will be forwarded to the local mesh.
Set to `false` by default for all channels.
### Uplink Enabled
If enabled, messages from the mesh will be sent to the **public** internet through any node's configured gateway.
Set to `false` by default for all channels.
<Tabs
groupId="settings"
defaultValue="cli"
values={[
{label: 'Android', value: 'android'},
{label: 'Apple', value: 'apple'},
{label: 'CLI', value: 'cli'},
{label: 'Web', value: 'web'},
]}>
<TabItem value="android">
:::info
Limited Channel Config options are available on Android. QR code scanning is available.
:::
</TabItem>
<TabItem value="apple">
:::info
Channel settings are only available on Apple platforms by scanning QR codes.
:::
</TabItem>
<TabItem value="cli">
:::info
All Channel config options are available in the python CLI. Example commands are below:
:::
:::tip
Because the device will reboot after each command is sent via CLI, it is recommended when setting multiple values in a config section that commands be chained together as one.
```shell title="Example:"
meshtastic --ch-set name "My Channel" --ch-set psk random --ch-set uplink_enabled true --ch-index 4
```
:::
### Id
```shell title="Set the PRIMARY channel ID"
meshtastic --ch-set id 1234 --ch-index 0
```
### Name
```shell title="Set channel name for the PRIMARY channel"
# without spaces
meshtastic --ch-set name MyChannel --ch-index 0
# with spaces
meshtastic --ch-set name "My Channel" --ch-index 0
```
### PSK
If you use Meshtastic for exchanging messages you don't want other people to see, `random` is the setting you should use. Selecting `default` or any of the `simple` values from the following table will use publicly known encryption keys. They're shipped with Meshtastic source code and thus, anyone can listen to messages encrypted by them. They're great for testing and public channels.
| Setting | Behavior |
| :--------------------: | :-----------------------------------------------------------------------------------: |
| `none` | Disable Encryption |
| `default` | Default Encryption (use the weak encryption key) |
| `random` | Generate a secure 256-bit encryption key. Use this setting for private communication. |
| `simple0`- `simple254` | Uses a single byte encoding for encryption |
```shell title="Set encryption to default on PRIMARY channel"
meshtastic --ch-set psk default --ch-index 0
```
```shell title="Set encryption to random on PRIMARY channel"
meshtastic --ch-set psk random --ch-index 0
```
```shell title="Set encryption to single byte on PRIMARY channel"
meshtastic --ch-set psk simple15 --ch-index 0
```
```shell title="Set encryption to your own key on PRIMARY channel"
meshtastic --ch-set psk 0x1a1a1a1a2b2b2b2b1a1a1a1a2b2b2b2b1a1a1a1a2b2b2b2b1a1a1a1a2b2b2b2b --ch-index 0
```
```shell title="Set encryption to your own key on PRIMARY channel (Base64 encoded)"
meshtastic --ch-set psk base64:puavdd7vtYJh8NUVWgxbsoG2u9Sdqc54YvMLs+KNcMA= --ch-index 0
```
:::tip
Use this to copy and paste the `base64` encoded (single channel) key from the meshtastic --info command. Please dont use the omnibus (all channels) code here, it is not a valid key.
:::
```shell title="Disable encryption on PRIMARY channel"
meshtastic --ch-set psk none --ch-index 0
```
### Uplink / Downlink
For configuring gateways, please see [MQTT](/docs/settings/moduleconfig/mqtt)
```shell title="Enable/Disable Uplink on PRIMARY channel"
meshtastic --ch-set uplink_enabled true --ch-index 0
meshtastic --ch-set uplink_enabled false --ch-index 0
```
```shell title="Enable/Disable Downlink on SECONDARY channel"
meshtastic --ch-set downlink_enabled true --ch-index 1
meshtastic --ch-set downlink_enabled false --ch-index 5
```
</TabItem>
<TabItem value="web">
:::info
All Channel config options are available in the Web UI.
:::
</TabItem>
</Tabs>