These power cables connected to devices that either produced or consumed 12 volts. This cable could be connected to devices such as the Gl. ERZ400 b generator or the Feldfernschreiber (which consumed 12 Volts).

Here is a 2 meter 12 Volt power cable.

This is the 12 Volt cable plug. This plug can be connected to the Gl. ERZ400 b or the Feldfernschreiber.