Is it true that all PS models can playstation games now?

Question

Is it true that all PS models can playstation games now?
I dont have a PS,i only have an xbox and playstation but im thinking about getting the PS.I wanted the model that plays playstation games.my friend has a PS and he says all PSs can play playstation games online.he said theres something on the Playstation network that you can download which allows you to play PS games?is that true

Answer

I dont know what some of these other people are talking about. The first shipment of pss had a reader for the ps games, these units had some problems, one of which is shorting out and catching fire. Instead of fixing the problem sony decided to not even bother, so to answer your question, the very oldest ones are backwards compatible, the newer ones arent.