1. A remote control system, comprising: a remote controller having a microphone, a first input unit having a first actuator and a second input unit having a second actuator, the first input unit being operative to generate a speech recognition request signal; the second input unit being operative to generate a microphone request signal; and a receiving host, having: a speech recognition functional module, providing a speech recognition function, wherein the receiving host receives the speech recognition request signal from the remote controller to drive the speech recognition functional module to activate the speech recognition function so as to recognize speech signals received from the microphone of the remote controller after the speech recognition function is activated; and a microphone functional module, providing a microphone function, wherein the receiving host receives the microphone request signal from the remote controller to drive the microphone functional module to activate the microphone function, wherein the speech signals received from the microphone of the remote controller are being provided to the receiving host, and the speech recognition request signal and the microphone request signal are independently generated by the remote controller and then sent to the receiving host, such that the receiving host selectively performs the speech recognition function and the microphone function to process the speech signals; wherein: in a first mode of operation of the receiving host, the microphone function is activated and the speech recognition function is deactivated; and in a second mode of operation of the receiving host, the microphone function is activated and the speech recognition function is activated.