I recently acquired an FF33 field telephone frame to replace the magneto in another field telephone. The frame had a good ringer module and jack sockets. I had a wooden cigar box about the right size. So, I decided to make a reproduction AC auxiliary bell and it’s construction was described in a previous article on this forum (viewtopic.php?f=20&t=263300).
There is one thing about the AC auxiliary bell that makes no sense…. A double plug jack cord allows the bell to be plugged into the jack socket on an FF33 field telephone. The cord is only about 2 feet long, so the auxiliary bell cannot be located far from the FF33. This defeats the purpose of the auxiliary bell. Also, when the magneto of the FF33 is cranked, the auxiliary bell rings, which is not very desirable. For incoming calls, both the FF33 bell and the auxiliary bell ring. The only advantage is the increased ringing volume of two bells on incoming calls.
Now, the AC auxiliary bell also includes two binding posts. This allows the auxiliary bell to be connected by wires to a Tischfernsprecher 38‘s W2 terminals. The W2 terminals are for connection of an auxiliary bell. The wire can be any length, so the auxiliary bell can be located in another room or outside.
When the Tischfernsprecher 38 magneto is cranked the AC auxiliary bell is silent. When receiving calls, the Tischfernsprecher 38 bell and the auxiliary bell sound off. So, the auxiliary bell is best suited to be connected to a field telephone like the Tischfernsprecher 38.
Check out my WW2 German field telephone equipment blog... https://rotwangm.wordpress.com/wechsels ... er-part-2/