| 摘要 |
The present invention relates to powered audio peripheral devices such as audio headsets, which can be used both for the reception of stereo music signals from a cellular handset and for telephone voice signals, and where the power for the audio peripheral device is provided by the cellular telephone handset. The headset is provided with a pair of earphones, for use with the cellular telephone handset, and a USB connector for connecting the device to the handset over two connection paths. The headset is conditioned to operate in either a first mode, in which stereo signals are supplied from the handset to the earphones, or a second mode, in which mono voice telephone signals are supplied to both earphones. A switching unit in the device automatically derives operative power from the handset over one or the other of the connection paths, depending upon the mode of operation. It allows power to be supplied to the device from the handset over alternative pin connections.
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