I. Application Solution Market Analysis

With the rapid development of smart homes and community management, the smart home market is experiencing booming growth. According to relevant data, the global smart home market size is expected to continue growing, reaching a relatively high level by 2025. However, the market also faces three core challenges in its development: device fragmentation, network complexity, and fragmented user experience.

Smart devices in users' homes often come from different brands and use various communication protocols such as ZigBee, Wi-Fi, Bluetooth, and even wired connections, resulting in isolated data silos that cannot be managed or interconnected. For example, a user might own a smart light bulb from one brand using Wi-Fi and a smart door lock from another brand using ZigBee; it's difficult to achieve联动 control between these two devices. At the same time, traditional pure cloud control solutions suffer from high latency, privacy concerns, and the risk of loss of control due to network outages. When users control devices through the cloud, data needs to be processed by cloud servers, which may lead to delays in control commands, affecting the user experience. Moreover, user data is stored in the cloud, posing a risk of privacy leaks. Once the network is interrupted, users cannot control their devices, causing inconvenience.

Therefore, the market urgently needs a home control hub that can be deployed locally, is compatible with multiple protocols, and has edge computing capabilities. It should not be merely a simple gateway, but a "home brain" capable of connecting new and old devices, processing local logic, ensuring stability and privacy, and serving as a unified entry point for secure interaction with the cloud. Based on in-depth research of EBITE's product line, we have built a well-structured, stable, reliable, and cost-effective smart home whole-house control hub solution, using the E90-DTU(400SL30)E (LoRa Ethernet gateway) and E840-DTU(TCEC05-485) (4G Cat1 DTU) as its core.

II. Detailed Overview of Scenario Application Solutions

1. Core Architecture

This solution aims to build a two-layer smart home network architecture of "local core + remote redundancy," enabling unified access and intelligent linkage of devices across brands and protocols.

2. Core Value Propositions of the Solution

2.1 Multi-Protocol Local Integration
The E90-DTU(400SL30)E itself supports Modbus TCP/RTU protocol conversion. Combined with its Ethernet interface and LoRa wireless capability, it can act as a bridge, uniformly converting data from Zigbee coordinators (via serial port), LoRa nodes, and traditional 485 devices into TCP/IP protocol for processing by the central host. This means that regardless of the protocol used by devices in a user's home, unified management can be achieved through this gateway. For example, a user's home electricity meter using the traditional Modbus RTU protocol can have its data converted to TCP/IP protocol through the E90 gateway and transmitted to the central host, allowing the user to view the meter data on a unified interface.

2.2 High Reliability with Network Redundancy
The home broadband serves as the primary link, with the E840-DTU(TCEC05-485) acting as a 4G Cat1 backup link. When broadband is interrupted, the 4G DTU can automatically upload critical alarm information and status data to the cloud via the MQTT protocol, while maintaining the remote configuration channel, ensuring the system never "loses connection." For example, when home broadband fails, users can still receive alarm information from home security devices via the 4G network, ensuring home safety.

2.3 Edge Computing Reduces Latency All device linkage rules (such as "automatic light turn on when door sensor opens") run on a local central host, achieving millisecond-level response times. It does not rely on the external network, and network outages do not affect basic automation functions, while protecting user data privacy. In this scenario, when a user opens the door, the door sensor detects the signal and transmits it directly to the central host, which immediately triggers the light-on command with virtually no delay, significantly improving the user experience. Furthermore, data processing locally avoids the privacy risks associated with uploading data to the cloud.

2.4 Powerful Expansion Capabilities LoRa networks possess superior penetration and long-range characteristics, easily covering areas where Wi-Fi and Zigbee signals are difficult to reach, such as villas, multi-story houses, courtyards, and basements, solving the "last 100 meters" coverage problem for smart homes. For example, in a three-story villa, the Wi-Fi signal in the basement may be weak, but the LoRa signal can easily cover the basement, allowing users to use smart devices and control home appliances from there.

III. Detailed Implementation Steps of the Application Solution

1. First Phase: Hardware Deployment and Network Setup

1.1 Central Equipment Installation
Install a central host (such as a Raspberry Pi) in the home's weak current box or network center, and connect it to the home router via a network cable. Choosing a suitable installation location ensures the stability of the central host and the reliability of the network connection.

1.2 LoRa Gateway Configuration
Connect the E90-DTU(400SL30)E to the same router via a network cable.

Log in to its web configuration page using a computer (default IP or DHCP obtained), set it to TCP server mode, and open the port (e.g., 8887).

Enable its "Modbus Gateway" function's "Simple Protocol Conversion" to achieve automatic conversion between TCP and RTU protocols.

Configure the LoRa wireless parameters (frequency, channel, key) to ensure compatibility with subsequent LoRa sensors.

1.3 4G Backup Link Deployment
Connect the RS485 interface of the E840-DTU (TCEC05-485) to the serial port of the central host via a USB-to-485 cable or directly.

Set it to MQTT Client mode using its dedicated configuration tool or SMS, filling in the cloud MQTT server address (e.g., Alibaba Cloud IoT), port, and device triplet.

Configure it as a backup link, typically setting up a heartbeat and configuring it to actively resume data transmission when the primary link (which the central host can send specific commands via the serial port) fails.

1.4 Sensor Layer Device Pairing

LoRa Devices: Configure them with the same wireless network address, channel, and key as the E90 gateway to achieve automatic network access.

Zigbee Devices: Connect the Zigbee coordinator (e.g., CC2652P module) to the USB port of the central host, or connect a Zigbee serial port coordinator module to the E90 gateway. Complete device pairing using software such as Zigbee2MQTT on the central host.

Traditional RS485 devices: Directly connect to the RS485 interface of the E90 gateway and configure the corresponding Modbus TCP slave address in the central host software.

2. Second Phase: Software Integration and Rule Orchestration

2.1 Edge Computing Platform Deployment
Install Home Assistant (HA) or Node-RED on the central host. These platforms offer rich functionality and plugins, enabling device integration and automated rule creation.

2.2 Device Access to HA/Node-RED
For devices connected via the E90 gateway: Install “Modbus TCP” integration in HA, fill in the E90 gateway's IP address and port, and add LoRa sensors, Zigbee devices (converted by the coordinator), and RS485 devices as entities.

Cloud Device Integration: Configure integration with platforms such as Alibaba Cloud IoT in HA to synchronize devices already connected to the cloud via 4G DTU to the local interface.

Direct Wi-Fi Devices: Connect via the corresponding official or third-party plugins for HA.

2.3 Automated Rule Creation
Write local linkage rules within HA's "Automation" or Node-RED processes. For example:

IF LoRa human body sensor in the yard triggers AND time is night THEN Turn on LoRa smart street light AND Send WeChat push via 4G DTU.

IF Zigbee temperature and humidity sensor shows indoor temperature >26℃ THEN Control 485 air conditioning gateway to start cooling via Modbus TCP.

3. Third Stage: Cloud Synchronization and Remote Access

3.1 Data Cloud Synchronization
Configure HA to securely synchronize selected device status and logs to the cloud via its Cloud component or using the E840-DTU (TCEC05-485) MQTT connection for historical data viewing and remote analysis. Users can view historical data of home devices through the cloud to understand device usage.

3.2 Secure Remote Access
Through application development on the Alibaba Cloud IoT platform or HA's official remote services, secure remote control via mobile APP is achieved, allowing management of home devices via 4G/5G networks even when outdoors. Users can control home devices conveniently and quickly from anywhere via a mobile app.

IV. Communication Test Results for Smart Home Application Scenarios

1. Courtyard Security Linkage

Communication Path: LoRa PIR → E90 Gateway → HA → LoRa Light

Latency Test: From human presence detection to light activation, the entire local link latency is < 500ms. This means that when someone enters the courtyard, the light will quickly turn on, providing timely warning.

Reliability Test: In a courtyard corner (50 meters from the gateway, with a wall obstructing view), 100 consecutive triggers resulted in a success rate > 99.5%. This demonstrates the high reliability of the solution in complex environments.

2. Cross-Protocol Scenario Linkage

Communication Path: Zigbee Curtain Switch → HA → Modbus Air Conditioning Gateway

Protocol Conversion Test: The HA sends a "close curtains" command, which is accurately converted to a Modbus RTU command via Modbus TCP through the E90 gateway and sent to the air conditioning gateway, controlling the fan coil unit to reduce its fan speed. The conversion accuracy is 100%. This proves the accuracy and reliability of the solution in cross-protocol communication. 3. Network Redundancy Switching

3.Communication Path: Manually disconnecting home broadband.

Primary/Backup Switching Test: After broadband disconnection, the central host notifies the E840 4G DTU via serial port. Within 10 seconds, the "LINK" light on the 4G DTU illuminates, and fire alarm information is successfully uploaded to the cloud platform via MQTT and pushed to the mobile phone. This ensures timely transmission of critical information during network failures.

4. Long-Distance Data Acquisition

Communication Path: Basement LoRa Water Leak Sensor → E90 Gateway

Signal Strength Test: In the second basement level of a three-story villa, the E90 gateway can still stably receive sensor data, with an RSSI signal strength > -110dBm and a data packet reception rate > 98%. This demonstrates the advantages of LoRa networks in long-distance transmission.

5. Cloud Command Issuance

Communication Path: Mobile App → Cloud → 4G DTU → Serial Port → HA → E90 Gateway → Device

End-to-End Latency Test: Under good 4G network conditions, the end-to-end latency from clicking "Turn on Living Room Lights" on the mobile phone to the actual light response is < 2 seconds. This ensures the timeliness of remote control.