I just bought a new prius in oct . It's the basic unit with basic radio and single play cd player. My question is.... there is a plugin in the center arm rest, is this 12 volts out or is for inputing audio to the stereo ? There is one more plugin on the lower part of the dash. What is this ?

 

All the 07's have a power socket under the right side dash and a second in the center console next to an Audio In jack. Make sure you get a shielded audio cable, though, or else you'll get a lot of static when powering something on the console socket at the same time.