An audio/video source switching system comprising a control server , a computer network , at least one mobile device , and a switcher , wherein the switcher comprises: a microprocessor; a memory; computer-readable instructions stored in the memory and executing on the microprocessor; a plurality of audio/video source inputs ; an audio/video output ; and one or more computer network interfaces ; wherein the switcher is configured to receive a control frame comprising a control instruction from the control server via the computer network , and in response to the control instruction, to enter one of an update mode, active mode, and passive mode in accordance with the control instruction; wherein the update mode obtains audio/video data and updated computer-readable instructions from the control server via the computer network and to store the audio/video data and updated computer-readable instructions in the memory of the switcher ; wherein the active mode disconnects a first audio/video source input from the audio/video output and connect a second audio/video source input to the audio/video output; and wherein the passive mode listens for a control frame from the control server or for an audio streaming request received via the computer network from the mobile device , and in response to the audio streaming request, to stream an audio component of an audio/video signal emitted from the audio/video output to one or more mobile devices via the computer network ; wherein if a control frame received in the passive mode instructs the switcher to enter in active mode, the switcher is configured to automatically detect a change in a first audio/video signal received via a first audio/video source input, and in response to said detection of the change in the first audio/video signal, to disconnect the first audio/video source input from the audio/video output and connect a second audio/video source input providing a second audio/video signal to the audio/video output ; and wherein the first audio/video signal comprises a broadcast television signal comprising a first television program segment followed by a first commercial advertisement, wherein the change in the first audio/video signal is a transition from the first television program segment to the first commercial advertisement and wherein the second audio/video signal is a second commercial advertisement different from the first commercial advertisement. a microprocessor; a memory; computer-readable instructions stored in the memory and executing on the microprocessor; a plurality of audio/video source inputs ; an audio/video output ; and one or more computer network interfaces ; wherein the switcher is configured to receive a control frame comprising a control instruction from the control server via the computer network , and in response to the control instruction, to enter one of an update mode, active mode, and passive mode in accordance with the control instruction; wherein the update mode obtains audio/video data and updated computer-readable instructions from the control server via the computer network and to store the audio/video data and updated computer-readable instructions in the memory of the switcher ; wherein the active mode disconnects a first audio/video source input from the audio/video output and connect a second audio/video source input to the audio/video output; and wherein the passive mode listens for a control frame from the control server or for an audio streaming request received via the computer network from the mobile device , and in response to the audio streaming request, to stream an audio component of an audio/video signal emitted from the audio/video output to one or more mobile devices via the computer network ; wherein if a control frame received in the passive mode instructs the switcher to enter in active mode, <EOS>