Abstract: An audio-visual transmission device connected with a camera and a receiver is provided and includes a wireless module, a processor and a universal serial bus (USB) port. The wireless module is used for wireless connection with the camera to receive an audio-visual data transmitted from the camera. The processor transmits a connection request signal to the camera through the wireless module. The universal serial bus (USB) port is used for transmitting the audio-visual data. The camera transmits a connection acknowledgment signal and the audio-visual data back to the processor via the wireless module according to the connection request signal, and the receiver is connected to the audio-visual transmission device through the USB port to receive the audio-visual data.

Abstract: An audio-visual transmission device connected with a camera and a receiver is provided and includes a wireless module, a processor and a universal serial bus (USB) port. The wireless module is used for wireless connection with the camera to receive an audio-visual data transmitted from the camera. The processor transmits a connection request signal to the camera through the wireless module. The universal serial bus (USB) port is used for transmitting the audio-visual data. The camera transmits a connection acknowledgment signal and the audio-visual data back to the processor via the wireless module according to the connection request signal, and the receiver is connected to the audio-visual transmission device through the USB port to receive the audio-visual data.

Abstract: A key switch system for switching in a cyclic pattern between a plurality of wireless communication apparatuses of a computer, comprising a function key, mounted on the computer, for generating an interrupt signal after depression; software for activating and deactivating the wireless communication apparatuses according to the signal, with one activated at a time; and a display window for displaying the activated/deactivated status of the wireless communication apparatuses; wherein cyclic switching between the wireless communication apparatuses are enacted by the depression of the function key; the wireless communication apparatuses include incompatible ones; and the cyclic pattern follows the sequence of, firstly, activating in turn each one of the apparatuses in a round and then, secondly, deactivating all of the apparatuses after a round is finished and starting another round.