Soracom Air for Cellular

Downlink API

Overview

The Downlink API ( Sim:SendDownlinkSsh and Sim:SendDownlinkHttp ) enables downlink communications from the cloud to IoT devices.

Traditionally, cloud-to-device downlink communication has been challenging due to security concerns and network configuration complexities. The Downlink API addresses these challenges by accepting SSH or HTTP commands and data as inputs through the Soracom API, and securely transmitting the commands or data to devices via Soracom’s secure private network. This architecture ensures a simple and secure communication channel.

With the Downlink API, even legacy IoT devices can seamlessly integrate with the cloud as long as they accept communication over HTTP or SSH. Furthermore, when combined with low-code development environments like Soracom Flux, it enables the creation of more sophisticated IoT systems, such as automatically sending commands to devices triggered by sensor data or cloud-based events.

Comparison with Other Features

Soracom offers multiple options for downlink communication. The table below compares the Downlink API with other features:

Feature	Downlink API	Send SMS to Device	Soracom Napter	Remote Device Access using Soracom Gate
Description	Sends commands or data to devices and receives execution results	Sends data to devices	Provides on-demand remote access to devices	Allows continuous remote access to devices
Supported Communication Protocol	SSH, HTTP	SMS	TCP such as SSH, HTTP, VNC	Any
Max Data Size to Device	8 KiB (SSH), 5 MiB (HTTP)	140 B	Unlimited	Unlimited
Uplink Response to Downlink		-
Connection Duration	Until the API call completes	-	Until the on-demand remote access expires	Persistent

Use Cases

The Downlink API is intended for the following use cases:

Use Case	Description
Initial Parameter Setting (Provisioning)	Set the necessary configuration for manufacturing and deployment (Wi-Fi settings, authentication credentials, sensor thresholds, etc.) for each device.
FOTA (Firmware Over-the-Air) Updates	Remotely trigger firmware updates on devices, apply security patches, and add new features.
ONVIF-Compatible Cameras	Use the ONVIF (Open Network Video Interface Forum) protocol to control pan-tilt-zoom (PTZ) operations on IP cameras.
Configuration Changes	Modify settings of devices such as PLCs (Programmable Logic Controllers).
Accessing Device REST APIs	Interact with REST APIs on IoT gateways to retrieve sensor data and control relays.
Industrial Equipment Control (e.g., Traffic Lights)	Remotely control traffic lights in factories and warehouses (on/off, blinking, etc.).
IoT Lock/Unlock	Remotely control electronic locks for remote access management.
Log Collection	Retrieve device operation logs and error logs for monitoring and analysis.
Accessing Other Devices on a Local Network	Use the target device as a gateway to access other connected devices in the local network.
Alive Monitoring	Periodically check the operational status of devices and trigger alerts upon detecting anomalies.

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Programmatic Usage

Currently, Downlink communications can only be sent via the API and are not available in Soracom User Console.