1. Uvod
The EBYTE E31-230T33D is a 2W wireless transceiver module designed for reliable long-range data transmission. It operates in the 225-237.6MHz frequency band (default 230MHz) and features a UART interface for communication. This module incorporates the AXSEM AX5243 RF chip, offering half-duplex transparent transmission mode and TTL level output. Key features include Forward Error Correction (FEC) for enhanced data reliability, data encryption and compression, and support for a wide operating voltage opseg (3.3V do 5.2V).
This manual provides essential information for the proper setup, operation, and maintenance of your E31-230T33D module.

Figure 1: EBYTE E31-230T33D RF Module. This image shows the top view of the module, highlighting the heatsink, SMA antenna connector, and pin headers for M0, M1, RXD, TXD, AUX, VCC, and GND connections.
2. Karakteristike
- RF čip: AXSEM AX5243
- Učestalost: 225~237.6MHz (default 230MHz)
- Izlazna snaga: 24~33dBm (up to 2W), software adjustable
- Udaljenost prijenosa: Up to 8.0 km (actual testing)
- Interfejs: UART (TTL nivo)
- Brzina prijenosa podataka: 1.2kbps to 70kbps
- modulacija: Advanced ultra-narrow band GFSK
- Operating Voltage: 3.3V~5.2V (3.3V+ recommended for optimal performance)
- Radna temperatura: -40 to 85 °C (Industrial grade)
- Posebne funkcije: Forward Error Correction (FEC), Data Encryption, Data Compression, Air Wake-up (ultra-low power consumption)
- Usklađenost: FCC, CE, CCC compliant design
3. Podešavanje
3.1 Definicije pinova
The E31-230T33D module features several pins for power, data, and control. Refer to the pinout diagram for proper connection.

Figure 2: Pinout of the E31-230T33D module. This diagram illustrates the pin assignments for M0, M1, RXD, TXD, AUX, VCC, and GND, crucial for connecting the module to a host system.
| Pin | Ime | Opis |
|---|---|---|
| 1 | M0 | Mode selection pin 0 |
| 2 | M1 | Mode selection pin 1 |
| 3 | RXD | UART data receive (input to module) |
| 4 | TXD | UART data transmit (output from module) |
| 5 | AUX | Auxiliary pin (e.g., wireless wake-up indication) |
| 6 | VCC | Power supply (3.3V-5.2V) |
| 7 | GND | Ground |
3.2 Napajanje
Connect the VCC pin to a stable power supply within the range of 3.3V to 5.2V. For optimal performance, especially when transmitting at higher power, a supply voltage greater than 3.3V is recommended. Ensure the power supply can provide sufficient current for the module's operation, particularly during transmission peaks.
3.3 Antenska veza
The module features an SMA interface for antenna connection. Connect a suitable 230MHz antenna to this port. Ensure the antenna is securely attached and correctly matched for the operating frequency to achieve maximum transmission range and efficiency.
3.4 UART sučelje
Connect the RXD and TXD pins to the corresponding TX and RX pins of your host microcontroller or device. The module operates with TTL level UART signals. Ensure proper voltage level shifting if your host device uses different logic levels.
4. Načini rada
The E31-230T33D module supports various operating modes controlled by the M0 and M1 pins. These pins determine the module's behavior, such as transmission power, data rate, and sleep modes.
| M1 | M0 | Mode | Opis |
|---|---|---|---|
| LOW | LOW | Normalni način rada | Transparent transmission mode, module is always awake. |
| LOW | HIGH | Wake-up Mode | Module can be woken up by air data, suitable for low-power applications. |
| HIGH | LOW | Režim za uštedu energije | Module enters low power consumption state, suitable for battery-powered devices. |
| HIGH | HIGH | Configuration Mode | Used to configure module parameters via UART commands. |
Refer to the official EBYTE documentation for detailed commands and parameter settings in Configuration Mode. A relevant link for further information is available at www.cdebyte.com.
5. Uputstvo za upotrebu
5.1 Prijenos podataka
In Normal Mode (M1=LOW, M0=LOW), the module operates as a transparent serial port. Any data sent to the module's RXD pin will be transmitted wirelessly, and any data received wirelessly will be output through the TXD pin. Ensure both transmitting and receiving modules are configured with compatible parameters (frequency, data rate, etc.).
5.2 Konfiguracija parametara
To change module parameters such as frequency, air data rate, UART baud rate, and transmission power, set the module to Configuration Mode (M1=HIGH, M0=HIGH). Use a serial port assistant or custom software to send specific configuration commands via the UART interface. After configuration, return the module to Normal or Wake-up Mode for operation.

Slika 3: Prample application scenarios for the E31-230T33D module. This image illustrates potential uses in industrial automation, smart homes, smart farming, and hotel projects, demonstrating the module's versatility.
6. Održavanje
The E31-230T33D module is designed for industrial-grade reliability and requires minimal maintenance. However, adhering to the following guidelines can ensure long-term stable operation:
- Uslovi okoline: Operate the module within the specified temperature range of -40°C to 85°C. Avoid exposure to extreme humidity, corrosive gases, or strong electromagnetic interference.
- Stabilnost napajanja: Ensure a stable and clean power supply. Fluctuations or noise in the power supply can affect module performance and longevity.
- Integritet antene: Periodically check the antenna connection for tightness and ensure the antenna itself is not damaged. A damaged or improperly connected antenna can significantly reduce transmission range and efficiency.
- ESD zaštita: The module is an ESD sensitive device. Always handle it with appropriate electrostatic discharge precautions to prevent damage.

Figure 4: Environmental testing of the E31-230T33D module. This image shows the module being tested in a high and low temperature chamber, demonstrating its robustness for operation in extreme cold and hot environments (-40°C to +85°C).
7. Otkrivanje problema
Ako naiđete na probleme s vašim E31-230T33D modulom, razmotrite sljedeće korake za rješavanje problema:
- Nema komunikacije:
- Provjeriti voltage and connections (VCC, GND).
- Check UART connections (RXD, TXD) and ensure correct baud rate settings on both the module and host device.
- Confirm the module is in the correct operating mode (e.g., Normal Mode for transparent transmission).
- Poor Range/Unreliable Transmission:
- Ensure the antenna is securely connected and suitable for 230MHz.
- Check for obstructions or sources of interference between the transmitting and receiving modules.
- Verify that both modules are configured to the same frequency and air data rate.
- Increase transmission power if possible (via Configuration Mode).
- Ensure the power supply can deliver sufficient current, especially during transmission.
- Module Not Responding to Configuration Commands:
- Ensure the M0 and M1 pins are set to Configuration Mode (HIGH, HIGH).
- Verify UART connections and baud rate.
- Check the format of the configuration commands against the official documentation.
8. Specifikacije
| Parametar | Vrijednost |
|---|---|
| Model | E31-230T33D |
| RF čip | AXSEM AX5243 |
| Frekvencijski opseg | 225~237.6MHz (default 230MHz) |
| Transmit Power | 24~33dBm (2W max) |
| Communication Distance | Do 8 km (u vidnom polju) |
| Interface | UART (TTL) |
| Brzina prenosa podataka | 1.2kbps to 70kbps |
| Operating Voltage | 3.3V~5.2V |
| Radna temperatura | -40°C do +85°C |
| Dimenzije | 60 mm x 37 mm (približno) |
| Težina | 23.6 ± 0.1 g |

Figure 5: Dimensions of the E31-230T33D module. This image shows the module with its approximate length of 60mm and width of 37mm, providing physical specifications for integration.
9. Garancija i podrška
For warranty information, technical support, and further documentation, please visit the official EBYTE webstranicu ili kontaktirajte njihovu korisničku službu. Proizvođačeva webstranica je www.cdebyte.com.
EBYTE products are designed and manufactured to high standards. In case of any issues, please refer to the troubleshooting section first. If the problem persists, contact EBYTE support with your product model and a detailed description of the issue.





