What is this cord for!?

Question

One end is a 2.5 mm earphone jack and the other end is a usb (not the end that plugs to the computer the smaller one used for digital cameras and mp3 players!)

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Answer 1

Sounds like an adapter for a cellphone. Probably for a Motorola. It's so you can use a headset on almost every Motorola phone since many of them have a mini "b" type USB connector.