We had a few years ago to install a 1930's era phone (made in Germany, still with a small swastika inside) that was used in a oil refinery. It was an "anti-explosion" phone, where all the electric part was double isolated from the outside so as not to spark any inflammables.
We tried to make it work with a Cisco ATA device. The device was already changed in the 80's to support nowadays electrical voltage, but otherwise still worked fine. The rotary dial was useless, as the ATA did not support it. But as it was configured as a PLAR line, it did its job flawlessly.