OB-05

The OB 05 telephone was a local-battery device. It was manufactured from 1905 to the mid-1920s. This device was the most widely used by the Reich Telegraph Administration and the Reich Post . From 1905 to 1918, the imperial eagle was depicted on the front and back of the device as a national emblem. After World War I and the abdication of the Kaiser, the emblem was painted black. The voice coil and the ringing circuit are built into a metal casing. The base and top of the metal casing are made of wood, which are painted black. This particular device has two cranks for the inductor. One on the left side and one on the right. Its operation is simple, when the handle is out of the fork and we turn the crank, it produces alternating current and sends call tones to the telephone exchange, (ringing). For the local operation of the device, the voltage to power the microphone was supplied by a battery placed next to the device. Apart from Public Services, at that time, not everyone could buy a telephone, so these devices belonged to someone wealthy or to a central store in each area, usually a coffee shop.