Abstract:By adopting 433 MHz radio frequency technology, the design uses the STM32 as the SCM to serve as the central controller so as to construct the long distance wireless calling network.Firstly, the embedded technology is used for the realization of sending and receiving of signals from the 433 MHz wireless calling system;then through the use of single chip machine, the 433 MHz radio frequency signals are decoded, and by aid of the BT module, the decoded signal is sent to upper machine by BT module.Thus the upper machine can receive the calling signal and process the signal promptly.The wireless calling system can rid the existing wired system the disadvantages of its wiring complexity, inconvenience of maintenance, and its equipment being irremovable.Therefore the wireless calling system boasts its low cost, high quality and satisfactory operability and thus can find wide application in public places.