First, you need to remove the hook-switch that is mounted above the ringer. So if you'd like to make a DIY-Ringer, all you need to take from this phone is the ringer mechanism itself that consists of the two coils in the middle and the mount that also holds a permanent magnet and the clapper. Of course, all this is now history as VOIP took over that merely emulates analog telephone lines. 60 VAC/25 Hz on the line and that AC current "didn't mind" the capacitator and so the ringer struck the two well-aligned metal bells to produce the clear and high beating ring. As now someone called that subscriber number, the switch-station applies ca. It charged itself on the DC current which thus couldn't pass. The post office relied upon not every subscriber requesting a line at the same time to keep cost low.), the capacitator is needed. In order to block the DC current and as such keep the line-finder switch at the switch station available (The line-finder was the first step in the automatic switch station and replaced the human operator, who answered "Hier Amt, was wird gewünscht?/Operator, what is requested?" There weren't as many line-finders as there were subscribers. As the receiver was hung up, the hook switch disconnected the phone circuit but connected the ringer circuit to the line. 60 VAC/25 Hz ringer current (Some went up to almost 120 VAC, so tampering with the line could sometimes very well result in quite painful, in any way dangerous experiences.). english, french or american) phone systems, but I guess they were all based on the same principles so there weren't any essential differences, and the german phone system operated with ca. I don't know any specifics about foreign (e. The capacitator doesn't serve any oscillating purpose here and party-lines were (and still are for legal reasons) uncommon in Germany. Entering "W49" and "Schaltplan" or "Stromlaufplan" in any search engine should produce satisfying results as to the circuit diagram. The phone as shown on the photograph is a German-made, postwar model W49 (Wählfernsprecher 49, post office nomenclature) which was an extraordinary developement of a desktop phone that could be converted to a wall-mounted by only losening a few screws and rotating the dial mechanism and hook-mount.
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