1. Long-distance wireless transmission (up to 500m in open area, 10kbps air data rate). 2. Operating frequency range: 433 - 458.5MHz, supports up to 255 communication channels. Maximum transmit power: 100mW (20dBm), with 10 adjustable power 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 over-the-air data rate (10kbps to 100kbps). 5. Features a three-minute configuration window after power-on during which the module can be set to AT mode by sending 'AT+ENABLE=1' for parameter adjustment. After this period, the module operates only in data transmission mode and AT commands are treated as regular 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: -40dBm to +20dBm Receiver Sensitivity: -114dBm Operating Temperature: -25°C to +75°C 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 Recommended for use with two or more units: - For 2 units: Module 1 and Module 2 communicate bidirectionally. - For 3 or more units: One master unit and multiple slave units. Operates similarly to wired RS485 bus. The 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 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 systems Access control systems Smart metering Color: Blue Material: Plastic + Metal Package Contents: 2 x 433M-458M VHF/UHF Radio Modem RS485 Transceiver (with enclosure) Note: Other accessories not included. Note: Slight color variation may occur due to lighting and display differences. Measurement tolerance: ±1-3cm.