Serial port module,Built-in program, no need to pay attention to serial protocol automatic networking. Serial wireless module,The open environment transmission distance is 1KM. Wireless serial module,The module supports one-to-one, one-to-many, many-to-one, many-to-many connections. Four transparent transmission modes to suit different applications. Wireless Serial Port Module,Built-in MCU, of programming, communication with external devices via serial port. Hc-12 Module,Not limited to the number of bytes sent in a single transmission (FU1/FU3 mode).