01-19-2012, 02:06 PM
Which model stereo are you looking at first of all?
Generally speaking, most USB ports on stereos will either be solely for data transfer/play control from other usb devices (thumb drives, portable hard drives, or mp3 players), or in some cases specifically for iPod/iPhone integration. In the latter, an Apple port to USB data cable would usually be included.
In order for a 1/8" (3.5mm) audio line to relay sound into a USB port, there has to be a converter (such as this)
to make the incoming analog voltage into a digital signal that the headunit can use through it's USB port. Plugging one of those cables into a Starmate probably wont damage it, but you wont get any sound through the stereo.
I've definitely seen stereo models that have USB in but no aux or RCA in, but they are very rare. Are you sure there are no inputs hidden on the back?
Samsung Galaxy Nexus
Creative Zen Vision M 60 GB
Audio Technica ATHM50/Shure E2C Headphones
and Vestax VCI100/Traktor Pro
Indians & Browns Together in PAIN