USA spec pa-15 toy install question

[4runnerAzGuy]

I pulled everything apart and got the head unit out but where do I actually plug it into the head unit? I bought it used so I didn't get a manual or anything for it. It looks like all the plus in the back of the unit are being used already

 

[phishtaco]

It plugs where the cd changer is supposed to be hooked up. Do you have a cd changer installed?

 

[4runnerAzGuy]

No i don't have the cd changer. I called USA spec and they told me I have the wrong plug since I don't have the t plug.