1. Longdistance wireless transmission up to 500 meters in open area, 10kbps speed in the air.2. Working frequency range 433 458.5 MHz, up to 255 communication channels. Maimum 100mW 20dBm transmitter power 10 levels of power can be set.3. Builtin MCU, use serial port to communicate with eternal devices. Send 31 bytes at a time.4. The module can support onetoone, onetomany transparent transmission communication through ID setting. Changing the speed of another serial port will synchronously change the speed at which data is sent over the air. 10kbps100kbps5. Set the critical three minutes. The module can send and receive data normally within three minutes after power on. You can send AT ATENABLE1 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, ATENABLE1 will also be sent out as data, there is no reserved word at this time.Product Name VHFUHF Radio Modem RS485 Wireless TransmitterReceiver 20DBM 433mhz Transmitter and ReceiverWorking voltage 4.5V5.5VInterface RS4855V GND A BFrequency 433MHzTransmitter power 4020dBmReceiver sensitivity 114dBmWorking temperature 25 Celsius75 CelsiusTransparent transmission mode speed 1200 2400,4800,9600Default,19200Open ground transmission distance 500MSize without antenna 74 24 16mmRecommended for more than 2 peopleHow to use more than 2 pcs12 pcs, Module 1 and Module 2 send data to each other.2 more than 3 pcs, One as master unit, the other one will be as slave unit.the way they work like a wired RS485 bus. The master sends data, the slave units receive all data. All slave units send data, the master and the other slave units can receive. At any given time, only one unit master or slave is allowed to send data.ApplicationIP PTZ cameraModbus Modbus temperature sensorLED controllerR4D3C32 N4D8B08 N4D8C12 RS485 RelayRemote control, remote control systemWireless meter,Home automation, Wiser HomeAccess controlSmart meterColor blueMaterial Plastic MetalPackage contents2 433M458M VHFUHF Radio Modem RS485 TransmitterReceiver with shellOnly the above package contents, others are not included.Note Light and different displays may cause the color of the item in the picture to be slightly different from the real thing. The measurement allowed error is 13cm.