SWITCHBOARD UNIT (Vermittlungskastchen mit kugelzeichen)

The unit is a varnished rectangular wooden box 100 mm wide and 105 mm tall. The front face is made up from three pieces of wood. In the left centre of the middle of the box are two circular metal lined holes with a 5 mm screw to the side of each. The holes are 30 and 40 mm from the left edge of the box and approx. 52 mm from the bottom of the box. Above the holes the following is engraved into the wood:
Abfrage – App.

The opposite (rear) side of the box is fashioned the same as the front but is completely bare, with the exception of the word – Deckel (cover) - in the centre of the top strip.

On top of the box on the LHS are two staggered knurled metal knobs, approx. 18 mm in diameter, that screw onto two metal plates for making an electrical connection. Behind these is an squat upright cylinder, approx. 20 mm high, with a knurled top of approx. 36 mm diameter. This has a clear plastic dome through which two small balls can be seen. It is assumed that this is a warning that the device is in operation.

On the right hand side of the wooden box, from top to bottom, there is:-
A metal slide holder attached by three small screws.
A red varnished wooden lever approx. 31 mm long and 10 mm thick with the words Dauer-sprechen (speaking duration) engraved and painted white. Under this are two approx. 12 mm diameter knurled metal knobs attached to a metal board that is screwed into the box by a screw at its centre. Attached to the right hand side is a slide that appears to be able to be rotated to the left to join the two knurled knobs into a circuit. Directly under this in the centre of the side is a cylindrical slot for a metal prong connector. Under this hole is a plain metal plate (approx 25 x 8 mm) riveted to the wood that has engraved in it the words:- Vermittel-Kl (Intermediate Kl). Under this plate is another cylindrical slot for a metal prong connector on the LHS and on the right is an electric cable (approx. 755 mm long) to the end of which is a Brass metal prong connector. Under these and slightly to the left is another plain metal plate bearing the word:- Ruheklinke.

On the left hand side of the box at the top is a metal handle riveted to the box. Under this engraved into the wood is the Siemens-Schuckert company logo and underneath this is the serial number “138522” in figures approx. 6 mm high. Directly under the serial are two approx. 12 mm diameter knurled metal knobs attached to a metal board that is screwed into the box by a screw at its centre. Attached to the left hand side is a slide that appears to be able to be rotated to the right to join the two knurled knobs into a circuit. These are the same as those on the other side but opposite handed. The two plates on each side of the box are both 45 mm from the base of the box. A circuit diagram marked on a 28 x 39 mm metal plate is riveted to the box directly under the two knurled knob metal plate.

The metal prong at the end of the electrical cable has the first 50 mm covered by a spring. Then the prong proper is brass with an approx. 11 mm x 17 mm diameter connector, an insulted handle (approx. 40 long and 16 mm diameter) and the prong is approx. 34 mm long.

This unit was used by soldiers of the German Army to quickly create a small telephone exchange where different lines came together. It was connected to a telephone set and provided a visible signal when a telephone call came in.