A Klappenschrank was a piece of equipment in the early days of the telephone, that was used to connect two subscribers with each other.
It was operated by a Fr√§ulein vom Amt and was effectively a board made up of holes – one hole per line, covered with a small cap.¬† The caps would flap to show that someone wanted to make a phone call, and often a light bulb would show that a line was still in use.¬† Two holes would be connected by a wire to establish the call between the two parties.
They stopped being used on the telephone network in the western German states in 1966, and in the GDR in 1987.
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