Patent ID: 7544089

Claim:
An adapter comprising: a first universal serial bus (USB) interface having a power pin, a first data pin, a second data pin, and a ground pin; a second USB interface having a power pin, a first data pin, a second data pin, and a ground pin, the pins of the first USB interface respectively connected to the pins of the second USB interface correspondingly, wherein the types of the first and second USB interfaces are different; and an audio interface having a left ear audio pin, a right ear audio pin, and a ground pin, the left ear audio pin of the audio interface connected to the first data pin of the second USB interface, the right ear audio pin of the audio interface connected to the second data pin of the second USB interface; wherein the first and second USB interfaces are capable of connecting between two corresponding electronic devices respectively for communicating the two electronic devices; the second USB interface and the audio interface are capable of connecting between two corresponding audio devices respectively for transmitting audio signals between the two audio devices, wherein a first variable resistor is connected between the left ear audio pin of the audio interface and the first data pin of the second USB interface, a second variable resistor is connected between the right ear audio pin of the audio interface and the second data pin of the second USB interface.