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  • ※ Long-distance wireless transmission (opening 1200 m/FU4 mode, air baud rate 1000bps)
  • ※ Operating frequency range (433-458.5MHz, up to 255 communication channels)
  • ※ Maximum 100mW (20dBm) transmit power (8-speed power can be set)
  • ※ Four working modes, suitable for different applications
  • ※ Built-in MCU, communicate through serial port and external device
  • ※ The number of bytes sent at one time is up to 256 bytes.
  • ※ Module supports one-to-one, one-to-many, many-to-many connection transparent transmission


The GT-38 wireless serial communication module is a new generation of multi-channel embedded wireless data transmission module. The wireless working frequency band is 433-458.5MHz, and multiple channels can be set. The stepping speed is 100KHz, and there are 255 channels in total. The module's maximum transmit power is 100mW (20dBm), the receiving sensitivity is -116dBm at 5000bps air baud rate, and the open distance can reach 1200m communication distance.
The module adopts stamp hole encapsulation and can be patch-welded. The module size is 26.7mm×12.9mm×6mm (including antenna cap, including spring antenna), which is convenient for customers to embed in the application system. The module has a PCB antenna holder ANT1. The user can use the 433M frequency band external antenna through the coaxial line. The module also has an antenna welding hole ANT2, which is convenient for the user to solder the spring antenna. The user can select one of the antennas according to the requirements of use.
The module contains MCU inside, the user does not need to program the module separately, and various transparent transmission modes can only send and receive serial port data, which is convenient to use. The module adopts a variety of serial port transparent transmission modes, and the user can select with AT commands according to the usage requirements. Four modes FU1, FU2, FU3, and FU4 have an average operating current of 3.6mA, 80μA, 16mA, and 16mA in idle state, and the maximum operating current is 100mA (at full power emission state).

Basic Specification

  • Model GT-38
  • Module size 26.7×12.9×6mm
  • Chip Solution SI4438
  • Working frequency band 433~458.5MHz
  • Communication Interface UART 3.3V/5V TTL Level
  • Antenna interface spring antenna / antenna socket
  • Working voltage 3.2~5.5V
  • Sleep current no sleep mode
  • Communication level 3.3V/5V level
  • Working humidity 10%~90%
  • Transmit power 20dBm (MAX)
  • Working temperature -25°C~+75°C
  • Reference distance 1200m
  • Storage temperature -40°C~+85°C

Working Method

2019-05-15 194648.png

As shown in the figure above, the GT-38 module uses 亍 instead of the physical connection for half-duplex communication. The device on the left sends the serial port data to the module. After receiving the serial port data, the RXD port of the module automatically sends the data to the air by radio waves. The module on the right can be automatically received and the serial port data sent by the original left device is restored from TXD. The same is true from right to left. Modules can only work in half-duplex mode and cannot send and receive data at the same time.