GM 21 pin radio, 7 more pins?

I am looking for a diagram that shows what each pin does on my factory cassette deck in my pontiac, but all i can find is the pins for speakers, backlighting, ignition power etc, but there are 7 more pins on the deck that i cant figure out, does anyone out there know what they are for?

yeah i kinda figured that

but i would like to know what each pin does individually, like which pins are left and right signals, which supply power to the tape deck or cd player ect

thanks

the car is a '95 grand am, the radio has a tape deck built in, i know for sure are AUX in, my buddys '94 sunbird has the same plug, these 7 pins run to his CD player in the lower part of the dash, i want to see if i can hook a CD player up to it maybe have it sit in the center console

Yup, sorry bro, your car's factory radio is just an updated 80s model, dates back to 84. most of the 7 pins you have do nothing, two of them are for illumination for accessories on different model cars. Go on ebay, you can pick up a factory radio with the right connections for under a hundred bucks, or just grab the CD model with the 7 band EQ, its a decent radio if you dont want after market.

peace

alright guys this wasnt much help but thanks just the same