Question Identify the existing audio setup and test if they work

[Vijay_network]

I bought a home and it already have a klipsch audio system (it was advertised, I haven’t verified it). I see an input panel for the Audi system. I guess these are banan plugs for 5 speaker setup. But there is also 1 extra input available which I am not able to identify. I have attached the image. Could anyone help out.

Also how to test the speakers before I buy anything. And if they are working what would be the specifications I should be looking in the receiver

 

[Oyeve]

Possible sub-woofer channel.

 

[Thump553]

My guess too. The best thing would be to look up the manual for the receiver once you know what model it is. Most manufacturers have pdfs of their manuals available online. The manual will also tell you the specs for supported speakers.