1. Long-distance wireless transmission (up to 500m in open area, 10kbps air data rate). 2. Operating frequency range: 433 - 458.5MHz, with up to 255 communication channels. Maximum transmit power: 100mW (20dBm), adjustable in 10 levels. 3. Built-in MCU; communicates with external devices via serial port. Transmits up to 31 bytes per packet. 4. Supports one-to-one and one-to-many transparent transmission via ID settings. Changing the serial port baud rate automatically adjusts the wireless data transmission rate (10kbps to 100kbps). 5. Features a three-minute configuration window after power-on. During this period, sending 'AT+ENABLE=1' command allows entry into AT mode for parameter settings. After three minutes, AT mode is no longer accessible and all commands are treated as data. 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: -25C to +75C Transparent Transmission Baud Rates: 1200, 2400, 4800, 9600 (default), 19200 Open Area Transmission Distance: Up to 500 meters Dimensions (without antenna): 74 x 24 x 16mm Usage Instructions (requires 2 or more units): - For 2 units: Module 1 and Module 2 can send and receive data with each other. - For 3 or more units: One unit acts as master, others as slaves. Operates similarly to wired RS485 bus. The master can transmit data to all slaves. Any slave can transmit data back to the master and other slaves. Only one device may transmit at a time to avoid collisions. Applications: IP PTZ Camera Modbus temperature sensor LED Controller RS485 Relay modules Remote control and remote measurement systems Wireless meter reading Home automation Access control systems Smart metering Color: Blue Material: Plastic + Metal Package Contents: 2 x 433M-458M VHF/UHF Radio Modem RS485 Transceiver (With Shell) Note: Other accessories not included. Note: Lighting and display differences may cause slight color variations between images and actual product. Measurement tolerance: 1-3cm.