This is the wall version of the famous Modell 27, also incorrectly known as the W28, SA 28 and Modell 28.
Vsa means it is a telephone equipment, wdst signifies it is a wall telephone and 38 it’s type number. This model may have various type numbers, depending on the electronics, handset, cord, etc.
Please see also the later O5 version, I have.
I bought this specimen over the internet in 2016, thinking it was a good parts phone. When it arrived it turned out, to my surprise, to be an early version, almost complete & original and not in a too bad state: a keeper!
Almost everything is original, except for the receiver and receiver cap.
The outside is in reasonable condition, so I hope to give it a full restoration in the future.
It is complete, down to the very last screw & bolt and even the cord is original.