speaker level input on an old Clarion amp

[automatic]

I just inherited an old Clarion APA 4202 from my roomate, it has a speaker level input on the back that looks you need some kind of proprietary plug/adapter to clip into it.
Any ideas how to use this input or will I still need to get line out converters to hook up my C43 deck?

[StereoInstaller1]

call around and find a Clarion dealer, one of the installers will likely have a plug sitting.

Use chassis ground for the negative, do NOT use the speaker negative from the deck, simply cap it off.

Luke