Pins and USB on the back of average modern car radio?

All modern car radios have these pins on the back, where goes USB cables (and USB cables are also part of the package).

What is the purpose of these USB cables? Can it be used to transfer data (eg. USB stick) and can it be used to charge device (eg. telephone)?

Also why one port has 4 pins and second port has 6 pins?

???

It really depends on the model of the stereo. Most of them will at the very least, allow you to plug in a USB stick with music. Some of the more inexpensive units will read music off your phone, but not output enough power to charge.

As far as the pins, that's just the type of connector they used. It's really worth reading the manual.

One may be for android and the other for apple, the manual would be way more helpful