3–RCA-to-USB Cable?

Solution 1:

I did some digging and found some useful information in a review on Amazon. As you suspected, there is no analog/digital conversion hardware in the cable, the RCA lines are tied directly to the USB pins. The reviewer says that he disassembled a cable and found this pinout:

• USB Ground and USB Data- -> Ground of all three RCA connectors
• USB Data+ -> Left audio and video composite pins
• USB Vcc -> Right audio pin

From that pinout, it is impossible for this cable to carry either a valid composite A/V signal (because the left audio and video composite pins are tied together), or a valid USB signal (because Data- and Ground are tied together). This cable is an elaborate—and surprisingly widespread—scam.

Solution 2:

According to the product description at Amazon, they are RCA-to-USB cables...

They plug into a camcorder via RCA, to display images/sound on certain "USB-enabled TVs and PCs."