Long-distance wireless transmission (up to 500 meters in open area, 10kbps baud rate in the air). Operating frequency range: 433 - 458.5MHz, up to 255 communication channels. Maximum transmit power: 100mW (20dBm), with 10 adjustable power levels. Built-in MCU, communicates with external devices via serial port. Sends up to 31 bytes at a time. Supports one-to-one and one-to-many transparent transmission through ID settings. Changing the serial port baud rate automatically adjusts the over-the-air data rate (10kbps to 100kbps). Features a three-minute window after power-on during which the module can enter AT mode for configuration by sending the command 'AT+ENABLE=1'. After this period, only data transmission and reception are allowed. 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. Transmit power: -40 to +20dBm. Receiver sensitivity: -114dBm. Operating temperature: -25°C to +75°C. Transparent transmission mode baud rates: 1200, 2400, 4800, 9600 (default), 19200. Open ground transmission distance: 500M. Dimensions (without antenna): 74 x 24 x 16mm. Recommended for use with 2 or more units. Usage (2 or more units): With two modules, Module 1 and Module 2 can send data to each other. With three or more modules, one acts as master and others as slaves. Operation is similar to wired RS485 bus. Master sends data to all slaves; any slave can send data to the master and other slaves. Only one device may transmit at a time. Applications: IP PTZ Camera, Modbus temperature sensor, LED Controller, RS485 Relay, Remote control, remote measurement system, Wireless meter, Smart Home, Home Automation, Access control, Smart meter. Color: blue. Material: Plastic + Metal. Package Contents: 2 x 433M-458M VHF/UHF Radio Modem RS485 Transceiver (With shell). No additional items included. Note: Lighting and display differences may cause slight color variation between image and actual item. Measurement tolerance: +/- 1-3cm.