The Ebyte EWM628-2G4T series (EWM628-2G4T12S, EWM628-2G4T20SX, EWM628-2G4T27SX) are new-generation 2.4GHz ISM band wireless data transceiver modules based on the SX1281 RF chip, featuring LoRa spread spectrum technology, full-duplex transmission, and automatic frequency hopping. With TX power ranging from 12dBm to 27dBm, they achieve a maximum communication distance of 4km while offering TTL level UART interfaces, carrier sense, automatic relay, and communication key encryption for robust B2B industrial IoT applications.
| Parameter | EWM628‑2G4T12S | EWM628‑2G4T20SX | EWM628‑2G4T27SX |
|---|---|---|---|
| Modulation Scheme | Next‑Generation LoRa Modulation Technology | ||
| Operating Frequency Band | 2400MHz‑2500MHz | ||
| Cache Capacity (Send Cache) | 2048Byte | ||
| Cache Capacity (Receive Buffer) | 2048Byte | ||
| Launch Length | 240 Btye | ||
| Air Speed | 8.8‑203.1Kbps | ||
| Blocking Power | 10dBm | ||
| Transmit Power | 12dBm | 20dBm | 27dBm |
| Operating Voltage | 2.3‑5.5V | ||
| Communication Levels | 3.3V | ||
| Emission Current | 35‑48mA (Instantaneous Power Consumption@12dBm) |
120‑160mA (Instantaneous Power Consumption@20dBm) |
260‑560mA (Instantaneous Power Consumption@27dBm) |
| Receive Current | 14‑15mA | 20‑22mA | 21‑23mA |
| Average sleep current | 5‑7uA | 6‑8uA | 6‑8uA |
| Reference Distance | 2.1km | 3.5km | 4km |
| Operating Temperature | -40‑+85℃ | ||
| Storage Temperature | -40‑+95℃ | ||
| Antenna Types | IPEX‑1/PCB | IPEX‑1/Postage Stamp Perforations | IPEX‑1/Postage Stamp Perforations |
| Interface Methods | 1.27mm Postage Stamp Perforations | ||
| Packaging Method | SMD | ||
| Dimensions | 28.7*17.5*2.8mm | 16*26*3.15mm | 40.5*25*4mm |
| Weight | ≈2.2g | ≈1.38g | ≈4.8g |
1. Key Features & Advantages
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Full-Duplex Transmission with FHSS: Utilizes SX1281 architecture to achieve true full-duplex LoRa communication alongside Automatic Frequency Hopping Spread Spectrum (FHSS), drastically reducing packet loss and interference in congested 2.4GHz environments.
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Extended 2.4GHz LoRa Range: Achieves up to 4km line-of-sight distance (with EWM628-2G4T27SX) by combining high 27dBm TX power with LoRa high receiver sensitivity, outperforming standard 2.4GHz FSK/BLE solutions.
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Integrated Auto-Relay & Security: Built-in automatic relay networking capabilities simplify mesh-like deployments, while hardware-level communication keys ensure data encryption against unauthorized interception.
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Universal TTL/UART Integration: Standardized UART interfaces with 3.3V logic compatibility allow for immediate plug-and-play integration with virtually any standard industrial MCU or PLC architecture without complex RF tuning.
| No. | Pin Names | Pin Orientation | Pin Functions |
|---|---|---|---|
| 1 | GND | Reference Location | Module Ground Wire |
| 2 | NC | - | Empty Foot (Please leave blank) |
| 3 | M0 | Input | The combination of M1 and M0 determines the module's four operating modes (must not be left floating; if not in use, connect to ground) |
| 4 | M1 | Input | The combination of M1 and M0 determines the module's four operating modes (must not be left floating; if not in use, connect to ground) |
| 5 | WKP | Input | The WKP control module enters sleep mode when the signal is low and remains awake when the signal is high (internal weak pull‑up) |
| 6 | RXD | Input | TTL serial input, connected to the external TXD output pin. |
| 7 | TXD | Output | TTL serial output, connected to the external RXD input pin. |
| 8 | AUX | Output | 1. Indicates the module's operating status (may be left floating); 2. During normal operation, a low level on this pin indicates a busy state, while a high level indicates an idle state; 3. It is not recommended to use this pin to drive external devices or to pull it low; otherwise, if the AUX pin is detected as being continuously pulled low by an external source during module power‑up, the module may be forced into upgrade mode and will not function normally. For detailed information, please refer to the instructions in Chapter 5. |
| 9 | VCC | - | Positive reference for modular power supplies, voltage range: 2.3 V to 5.5 V DC |
| 10 | GND | Reference Location | Module Ground Wire |
| 11 | GND | Reference Location | Module Ground Wire |
| 12 | NC | - | Open Pin (Please leave this pin floating; solder the pin. If possible, route it externally to facilitate future maintenance or firmware customization.) |
| 13 | NRST | Input | 1. Module reset pin. A low level triggers a reset, and the time the pin is held low must be greater than 100 μs; 2. It is strongly recommended that users connect this pin to a microcontroller to enable reset and recovery in the event of an unexpected situation. |
| 14 | NC | - | Open Pin (Please leave this pin floating; solder the pin. If possible, route it externally to facilitate future maintenance or firmware customization.) |
| 15 | NC | - | Open Pin (Please leave this pin floating; solder the pin. If possible, route it externally to facilitate future maintenance or firmware customization.) |
| 16 | NC | - | Empty Foot (Please leave blank) |
| 17 | LOCK | Output | 1. Module synchronization indicator pin: Active in frequency‑hopping full‑duplex mode; ignore in half‑duplex mode; 2. A high level indicates that the modules on both ends of the communication are synchronized and data transmission can proceed; 3. A low level indicates that the modules on both ends are not synchronized; transmitting data at this time will result in data loss. |
| 18 | NC | - | Empty Foot (Please leave blank) |
| 19 | NC | - | Empty Foot (Please leave blank) |
| 20 | GND | Reference Location | Module Ground Wire |
Industrial Installation & Wiring
The EWM628-2G4T series modules are designed as surface-mount (SMD) or through-hole components (depending on specific backplane integration). They require a clean 3.3V DC power supply. The communication interface utilizes standard TXD/RXD UART TTL pins (3.3V IO compatible, 5V systems require level shifting). Ensure the antenna trace routing maintains a 50-ohm impedance if using an external antenna via pad connection.
| No. | Pin Names | Pin Orientation | Pin Functions |
|---|---|---|---|
| 1 | NRST | Input | Module reset pin, low‑level reset |
| 2 | GND | Reference Location | Module Ground Wire |
| 3 | WKP | Input (Very Weak Pull‑Up) | The WKP control module enters sleep mode when the signal is low and remains awake when the signal is high (internal weak pull‑up) |
| 4 | NC | - | Open Pin (Please leave this pin floating; solder the pin. If possible, route it externally to facilitate future maintenance or firmware customization.) |
| 5 | LOCK | Output | 1. Module synchronization indicator pin; active in frequency‑hopping full‑duplex mode; not relevant in half‑duplex transmission mode; 2. A high level indicates that the modules on both ends of the communication have synchronized and data transmission can proceed; 3. A low level indicates that the modules on both ends of the communication have not synchronized; transmitting data at this time will result in data loss. |
| 6 | NC | - | Open Pin (Please leave this pin floating; solder the pin. If possible, route it externally to facilitate future maintenance or firmware customization.) |
| 7 | NC | - | Open Pin (Please leave this pin floating; solder the pin. If possible, route it externally to facilitate future maintenance or firmware customization.) |
| 8 | GND | Reference Location | Module Ground Wire |
| 11 | GND | Reference Location | Module Ground Wire |
| 12 | ANT | - | Antenna Connector (50 Ω Characteristic Impedance) |
| 13 | GND | Reference Location | Module Ground Wire |
| 14 | GND | Reference Location | Module Ground Wire |
| 15 | GND | Reference Location | Module Ground Wire |
| 16 | GND | Reference Location | Module Ground Wire |
| 19 | GND | Reference Location | Module Ground Wire |
| 20 | M0 | Input(Very Weak Pull‑Up) | The combination of M1 and M0 determines the module's four operating modes (must not be left floating; if not in use, they may be grounded) |
| 21 | M1 | Input(Very Weak Pull‑Up) | The combination of M1 and M0 determines the module's four operating modes (must not be left floating; if not in use, they may be grounded) |
| 22 | RXD | Input | TTL serial input, connected to the external TXD output pin |
| 23 | TXD | Output | TTL serial output, connected to the external RXD input pin |
| 24 | AUX | Output | 1. Indicates the module's operating status (may be left floating);
|
| 25 | VCC | - | Positive reference for modular power supplies; voltage range: 2.3‑5.5 V DC |
| 26 | GND | - | Module Ground Wire |
| No. | Pin Names | Pin Orientation | Pin Functions |
|---|---|---|---|
| 1 | GND | Reference Location | Module Ground Wire |
| 2 | NC | - | Empty Foot (Please leave blank) |
| 3 | NC | - | Empty Foot (Please leave blank) |
| 4 | LOCK | Output | 1. Module synchronization indicator pin: Active in frequency‑hopping full‑duplex mode, ignore in half‑duplex mode; 2. A high level indicates that the modules on both ends of the communication are synchronized and data transmission can proceed; 3. A low level indicates that the modules on both ends of the communication are not synchronized; transmitting data at this time will result in data loss. |
| 5 | NRST | Input | Module reset pin, low‑level reset |
| 6 | NC | - | Open Pin (Please leave this pin floating; solder the pin. If possible, route it externally to facilitate future maintenance or firmware customization.) |
| 7 | NC | - | Open Pin (Please leave this pin floating; solder the pin. If possible, route it externally to facilitate future maintenance or firmware customization.) |
| 8 | GND | Reference Location | Module Ground Wire |
| 9 | NC | - | Open Pin (Please leave this pin floating; solder the pin. If possible, route it externally to facilitate future maintenance or firmware customization.) |
| 10 | GND | Reference Location | Module Ground Wire |
| 11 | VCC | - | Positive reference for modular power supplies; voltage range: 2.3 V to 5.5 V DC |
| 12 | AUX | Output | 1. Indicates the module's operating status (may be left floating);
|
| 13 | TXD | Output | TTL serial output, connected to the external RXD input pin |
| 14 | RXD | Output | TTL serial input, connected to the external TXD output pin |
| 15 | M1 | Input | The combination of M1 and M0 determines the module's four operating modes (must not be left floating; if not in use, they must be grounded) |
| 16 | M0 | Input | The combination of M1 and M0 determines the module's four operating modes (must not be left floating; if not in use, they may be grounded) |
| 17 | WKP | Input (Very Weak Pull‑Up) | The WKP control module enters sleep mode when the signal is low and remains awake when the signal is high (internal weak pull‑up) |
| 18 | GND | Reference Location | Module Ground Wire |
| 19 | ANT | - | Antenna Connector (50 Ω Characteristic Impedance) |
| 20 | GND | Reference Location | Module Ground Wire |
| 21 | GND | Reference Location | Module Ground Wire |
| 22 | NC | - | Empty Foot (Please leave blank) |
Practical Application Scenarios
1. Smart Factory AGV Fleet Coordination
In industrial automation, AGVs (Automated Guided Vehicles) require continuous, real-time control. The EWM628-2G4T series' full-duplex transmission ensures that command signals from the central server and telemetry data from the AGV are transmitted simultaneously without collision. The Automatic Frequency Hopping (FHSS) guarantees stable links even in factories heavily congested with Wi-Fi interference.
2. Large-Scale Agricultural Drone Telemetry
For precision agriculture, drones flying over vast fields require reliable telemetry. The EWM628-2G4T27SX, providing a 4km transmission range and 27dBm output power, ensures uninterrupted long-range communication between the remote controller and the UAV. Its high data rate in the 2.4GHz band allows for faster parameter updates compared to traditional Sub-GHz LoRa, optimizing flight path accuracy.
3. Underground Mining Sensor Networks
In challenging mining environments where standard RF fails due to multipath fading, the LoRa modulation of the SX1281 chip penetrates complex layouts better than standard 2.4GHz FSK. By utilizing the built-in auto-relay function, multiple EWM628-2G4T12S modules can seamlessly form a multi-hop network, passing critical gas and temperature sensor data back to the surface control room.
4. High-Security Access Control Systems
For commercial building security, bidirectional real-time verification is critical. The integration of hardware-level communication keys ensures all badge scans and biometric data transmitted via the EWM628-2G4T20SX remain encrypted. The ultra-low latency of the module guarantees doors unlock instantaneously upon verification, improving user flow.
FAQ Section
1. What is the difference between standard Sub-GHz LoRa and this 2.4GHz LoRa module?
While standard Sub-GHz LoRa (e.g., 433MHz/868MHz/915MHz) is ideal for ultra-long-range with low data rates, the EWM628-2G4T series operates on the globally available 2.4GHz ISM band using the SX1281 chip. This allows for significantly higher data throughput and lower latency, while still retaining LoRa's excellent anti-interference and sensitivity properties, making it perfect for applications requiring both distance and speed.
2. Can I connect the UART interface directly to a 5V MCU system?
The EWM628-2G4T series modules operate on a 3.3V power supply and output TTL signals compatible with 3.3V IO logic. If you are integrating this module with a 5V MCU (like an Arduino UNO or industrial 5V PLC), you must use a logic level converter for the TX and RX lines to prevent permanent hardware damage to the RF module.
3. How does the Automatic Relay function work without an external gateway?
The built-in auto-relay protocol allows an intermediate EWM628-2G4T module to act as a repeater. When enabled, if a node cannot reach the master device directly, a middle node will automatically receive and forward the packet. This extends the overall network coverage up to twice the single-node distance without needing complex mesh software development or a dedicated LoRaWAN gateway.
4. Which EWM628-2G4T model should I choose for battery-powered wearable devices?
For compact, battery-operated devices, we highly recommend the EWM628-2G4T20SX or the EWM628-2G4T12S. The EWM628-2G4T20SX weighs only 1.38g and measures 16x26mm, offering an excellent balance of a 3.5km range and physical footprint. The 12S model consumes even less peak current, making it the most optimal choice for extreme low-power scenarios where 2.1km coverage is sufficient.
