1. Long-distance wireless transmission (up to 500 meters in open area, 10kbps air baud rate). 2. Operating frequency range (433 - 458.5 MHz, up to 255 communication channels). Max 100mW (20dBm) power (10 power levels can be set). 3. Built-in MCU, use serial port to communicate with external devices. Send 31 bytes at a time. 4. The module can support one-to-one, one-to-many transparent transmission communication through ID setting. Changing the baud rate of another serial port will synchronously change the rate at which data is sent over the air. (10kbps-100kbps) 5. Set \"critical three minutes\". The module can send and receive data normally within three minutes after power-on. You can send the AT command '' AT+ENABLE=1 '' to make the module enter the AT command mode for parameter setting. There is only this reserved word during these three minutes. After more than three minutes, you will not be able to enter the AT command mode, you can only send and receive data, ''AT+ENABLE=1'' will also be sent out as data, there are no reserved words at this time. Product name: VHF/UHF Radio Modem RS485 Wireless Transceiver 20DBM 433mhz Transmitter and Receiver Working voltage: 4.5V-5.5V; Interface: RS485(5V GND A+ B-) Frequency: 433MHz Power: -40~+20dBm; Receiver sensitivity: -114dBm; Operating temperature: -25 Celsius~+75 Celsius; Transparent transmission mode baud rate: 1200 2400,4800,9600(default),19200; Open ground transmission distance: 500M Size (without antenna): 74 x 24 x 16mm Recommend to buy more than 2 pcs How to use (more than = 2 pcs): 1/2 pcs, Module 1 and Module 2 send data to each other. 2 more than =3 pcs, one as master module, the other as slave module. how they work as well as wired RS485 bus. The master module sends data, the slave modules receive data. All slave devices send data, the master modules and other slave devices can receive. At any time, only one device (master or slave) is allowed to send data. Application: IP PTZ camera Modbus modbus temperature sensor LED controller R4D3C32 N4D8B08 N4D8C12 RS485 relay Remote control, remote control system; Wireless meter; Smart home, Home automation, Smarter home; Access control; Smart meter Color Blue Material: Plastic + Metal Package content: 2 * 433M-458M VHF/UHF Radio Modem RS485 Transceiver (With shell) Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3 cm.