ATT 1991 22A programmable pay phone

[Key2871]

Exactly. It's a working novelty. Jim (pay phone installer) said not to mess with the internal key pad. When I had one I was told the same thing. YOU could actually mess it up from default, so it will be a wall hanger, unless you put new guts in it. I had mine programmed but it changed, over a week or so. Then it truly was a dumb set. You have a seven digit working novelty that either way doesn't cost anything to make a call.
As I said of you want your money deposited returned, switch the two leads on the coin relay, and if you get a call that didn't go through, it will collect, but all your other calls will return. So either way, you win.
Just don't short or ground any thing in the phone, or it will cease to work at all.
It looks nice on the wall now, so enjoy it the way you have it.