“Melden, telefoon afnemen en knop even indrukken”: to call, take handset (telephone) and press button briefly. Only the handset points to Telefonbau & Normalzeit as the maker of this phone. Otherwise there are no signs pointing to any maker. It was made in the 2nd half of the 1930.
I have seen only one of them, although the paper refurbishment label from the 50s shows it was used by PTT and there must have been more. Otherwise they would not have refurbished it.
Normally I do not buy stuff like this, because I try to keep to automatic telephony.
The paper sign with instructions sparked my curiousity, so I bought it anyway.