It's a phone, a black phone. That's pretty much all I could determine about it. If I had to guess, I'd say it's from the early 90s, before cordless became the standard. Presumably, the manufacturer's name was on the cradle, which we never did find.
It took a lot of effort to get to the guts. I got one screw out, the only one I could find, but the case still wouldn't budge. I couldn't get a screwdriver tip under it either. Once again, when hand tools fail, you have to use the floor. I grabbed the phone by the cord and swung it like a flail at the concrete floor. It took about five minutes of smashing before the case split, at which point I noticed two cracked posts with screws in them.
Sure enough, I peeled off a little sticker above the keypad, and there were two screws, staring back like little mocking eyes. Hiding fasteners behind stickers or stick-on rubber feet is an old trick, and I usually catch it. Not this time, I guess.
There's not much worth saving out of a phone like this. I pretty much just took the buttons.