Features: Built-in program, no need to pay attention to serial protocol automatic networking. Support one to multiple interconnection and transparent transmission. The open environment transmission distance is 1KM. Operating frequency range (433.4-473.0MHz, up to 100 communication channels) Maximum 100mW transmit power. The module supports one-to-one, one-to-many, many-to-one, many-to-many connections. Four transparent transmission modes to suit different applications. Built-in MCU, free of programming, communication with external devices via serial port. Not limited to the number of bytes sent in a single transmission (FU1/FU3 mode). Default factory setting: working mode FU3, baud rate 9600bps, communication channel CH001 (433.4M). Specification: Voltage:3.2~5.5V(If the module is to be in the transmitting state for a long time, it is recommended to connect a 1N4007 diode in series when the power supply voltage exceeds 4.5V to avoid the built-in LDO heating of the module.) Distance:600m(The maximum communication distance can be adjusted to 1000m and the air baud rate is 5000bps) Default Standby Current:16mA( The working current of the module is different in different working modes ) Size:27.8 * 14.4 * 4mm / 1.09 * 0.57 * 0.16in Working Frequency:433.4~473.0MHz Maximum Transmission Wattage:100mW Package List: 1*Module 1*Spring Shaped Antenna