Patent ID: 7683974

Claim:
A detection method for a video interface outlet and earphone line outlet comprising the following steps: (1) allowing a detection device to detect whether a plug is inserted in a four-terminals outlet; and (2) allowing said detection device to detect whether an impedance value of a video output terminal of said four-terminals outlet is larger than a preset value; wherein said detection device comprises: a microprocessor connected to a plug detection terminal of said four-terminals outlet; a first switch chip with a first control signal input terminal, a second switch chip with a second control signal input terminal, and a control signal input terminal of a third switch chip being connected to said microprocessor; a transistor with a signal output terminal being connected to said microprocessor and further connected to said first and second switch chips through a plurality of resistors; a detection-use power supply input terminal being connected to said first switch chip; wherein said power supply input terminal communicates with said transistor and said second switch chip respectively through said resistors when said first switch chip is opened; said second switch chip is further connected to a video output terminal of said outlet; said microprocessor emits a signal to open said first switch chip and said second chip respectively through said first and second control signal input terminals when said microprocessor detects a message that a plug is inserted in said plug detection terminal; a detection-use power is caused to transmit to said transistor and said second switch chip, and said second switch chip relies on an output impedance value of said video output terminal to cause said signal output terminal to feedback a level state of said output impedance to said microprocessor; said microprocessor then emits a control signal to said third switch chip to cause said third switch chip to control an amplifier to output a video signal or not to output said video signal to said video signal output terminal.