1. Long-distance wireless transmission (up to 500m in open area, 10kbps air data rate). 2. Operating frequency range (433 - 458.5MHz, up to 255 communication channels). Maximum 100mW (20dBm) transmitting power (10 power levels can be set). 3. Built-in MCU, uses 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 rate on one serial port will synchronously change the rate at which data is sent over the air. (10kbps-100kbps) 5. Set the ''critical three minutes''. The module can send and receive data normally within three minutes of power-on. You can send AT ''ATandENABLE=1'' to make the module enter AT 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 AT mode, you can only send and receive data, ''ATandENABLE=1'' will also be sent out as data, there are no reserved words at this time. Product Name: VHF or UHF Radio Modem RS485 Wireless Transceiver 20DBM 433mhz Transmitter and Receiver Working Voltage: 4.5V-5.5V Interface: RS485(5V GND Aand B-) Frequency: 433MHz Transmitting Power: -40-and20dBm Receiver Sensitivity: -114dBm Operating Temperature: -25 Celsius-and75 Celsius Transparent Transmission Mode Rate: 1200 2400,4800,9600(Default),19200 Open Ground Transmission Distance: 500M Size (without antenna): 74 x 24 x 16mm Recommended to use more than 2pcs How to use (more than =2pcs): 1 or 2PCS, Module 1 and Module 2 send data to each other. 2 more than =3PCS, One as the main unit, the other as the slave unit. their way of working as wired RS485 bus. The main unit sends data, the slave units receive all data. Any slave unit sends data, the main unit and the other slave units can receive. At any time, only one device (main 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 measurement system Wireless meter ,Home automation, Wiser Home Access control Smart meter Color: blue Material: Plastic and Metal Package Contents: 2 x 433M-458M VHF or UHF Radio Modem RS485 transceiver (With shell) Only the above package content, other products are not included. Note: Light 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 1-3cm.