Node / meshtastic / Meshtastic-Android / files / docs / en / developer / transport.md

Displaying Rendered • View raw • Download

title: Transport

parent: Developer Guide

nav_order: 5

last_updated: 2026-05-13

aliases:

• ble

• serial

• tcp

• radio-transport

Meshtastic communicates between the app and radio hardware through multiple transport mechanisms.

The transport layer is abstracted through interfaces in T383838core/network and T383838core/ble, allowing the app to work identically regardless of the underlying connection type.

T282828

Module: T383838core:ble

Platforms: Android, Desktop (JVM via Kable), iOS (planned)

The primary transport for mobile devices and also available on desktop:

• Service discovery for Meshtastic GATT services

• Characteristic-based read/write for protobuf packets

• Connection state management and automatic reconnection

• MTU negotiation for optimal packet sizes

• T383838core/ble/ — BLE scanning, connection, and GATT operations

• Platform-specific implementations in T383838androidMain and T383838jvmMain (Kable)

Module: T383838core:network

Platforms: Android (OTG), Desktop

Serial communication over USB:

• Uses T383838usb-serial-for-android library on Android

• Direct serial port access on Desktop (JVM)

• Probe table for supported USB vendor/product IDs

• Automatic detection when USB device is connected

• Serial prober and transport factory in T383838core/network

• Desktop-specific serial in T383838desktopApp/src/main/kotlin/.../radio/

Module: T383838core:network

Platforms: Android, Desktop, iOS

Network-based transport for WiFi-enabled radios:

• TCP socket connection to radio's IP address

• Default port: 4403

• Used for development with simulated radios

• Available when BLE/USB is impractical

The T383838RadioTransportFactory interface abstracts transport creation:

T282828

Tff7b72interface T56d364RadioTransportFactory Tb4b4b4{

Tff7b72val Te6edf3supportedDeviceTypesTb4b4b4: Te6edf3ListTff7b72<Te6edf3DeviceTypeTff7b72>

Tff7b72fun Td2a8ffcreateTransportTb4b4b4(Te6edf3addressTb4b4b4: Tffa657StringTb4b4b4, Te6edf3serviceTb4b4b4: Te6edf3RadioInterfaceServiceTb4b4b4)Tb4b4b4: Te6edf3RadioTransport

Tff7b72fun Td2a8ffisMockTransportTb4b4b4(Tb4b4b4)Tb4b4b4: Tffa657Boolean

Tff7b72fun Td2a8ffisAddressValidTb4b4b4(Te6edf3addressTb4b4b4: Tffa657String?Tb4b4b4)Tb4b4b4: Tffa657Boolean

Tff7b72fun Td2a8fftoInterfaceAddressTb4b4b4(Te6edf3interfaceIdTb4b4b4: Te6edf3InterfaceIdTb4b4b4, Te6edf3restTb4b4b4: Tffa657StringTb4b4b4)Tb4b4b4: Tffa657String

Tb4b4b4}

Platform-specific implementations:

• Android: Supports BLE + USB + TCP

• Desktop: Supports BLE (Kable) + USB + TCP

• iOS: Planned BLE + TCP

1. Discovery — Scan for available radios (BLE scan / USB detect / manual TCP)

2. Connection — Establish link to selected radio

3. Handshake — Exchange node info and configuration

4. Active — Normal message exchange

5. Disconnection — Clean teardown or error recovery

1. Implement T383838RadioTransport interface

2. Register in platform-specific T383838RadioTransportFactory

3. Add connection UI in T383838feature:connections

4. Update DI bindings for the platform