| 摘要 |
A universal serial bus (USB) device adapter includes first and second conversion circuits, a switch unit, and a USB interface. The first conversion circuit includes a digital to analog (D/A) converter and a first coupler. The second conversion circuit includes an analog to digital (A/D) converter and a second coupler. When the switch unit connects the first conversion circuit to the USB interface, the D/A converter converts the digital signals representing data into an analog form suitable for transmission over an AC voltage as a carrier wave. The first coupler couples the analog form to a first alternating current (AC) voltage. When the switch unit connects the second conversion circuit to the USB interface, the second coupler decouples and separates the first AC voltage from the analog form data. The A/D converter converts the analog form data into digital data, and outputs the data to the USB interface.
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