Made by Telephon- und Telegraphenfabrik Czeija, Nissl & Co in Vienna, this is a variant of the so called “Antwerp phone”. Collectors call this model the “Antwerp phone” because it was originally designed by BTMC in Antwerp. BTMC was part of the Standard Electric company and from Antwerp this design spread, with local adaptations, over the other Standard Electric branches all over the world.
In this case only the bakelite housing is the same as the Antwerp phone. Although the lay out of the electrical components on the base plate is the same, there are of a different design than on the original model. The handset and dial are different too. The dial is even an American Electric design.
Unfortunately I have not been able to find out what the name or type designation of this Austrian variant is. Also there was not diagram on the inside.
See also the BTMC 2724
A fellow collector was kind enough to send me 2 diagrams for this model: