Wall phone decanter

This belonged to my great-grandmother (I'm 37) who gave it to my father when he was young so it must be at least a hundred years old. I have not been able to find anything like it online, not sure why. It's a wall phone that holds a liquor decanter. There is a label engraved in the wood on the front that says GES GESCHÜTZT which apparently means it was made in Germany. Jim bean made wall phone decanters but I have not been able to find anything that looks like this. Showed it to an antique dealer who had never seen anything like it. He researched it extensively as well and could not find any information. He offered to buy it but I declined because I would like to know more about it.