The Swiss Army Artillerie Telephon was developed by Siemens & Halske in 1913. At that time the Swiss Army had already a Siemens & Halske field telephone in operation, the leather backpack based Feldtelefon (F Tf) 1909, using the same basic setup with a buzzer for signalling and the same handset and headset. From 1915 to 1917 about 1500 pcs. were delivered to the Swiss field artillery forces. At the same time about 500 of the Zerlegbares Telephon (Take-apart Telephone) version were acquired .
The instrument can only be used with buzzer signalling either point to point to other instruments (also with signalling whistle using the headset) or to switchboard equipment with buzzer compatible call indicators. In 1935 all instruments were refurbished with new types of RX and TX elements and new pluggable headsets. The capacitors were replaced and new inert gas lightning arrestors were added. The instrument is still mentioned in the regulations of 1941 . During WWII the instruments were retired and replaced by the A.Tf.32 .
Description from "Vorschriften für den Telefon- und optischen Signaldienst der Artillerie"  (Translated from german):
16. The artillery telephone (Art.Tf.). It is installed in a wooden box with a carrying strap. To store the Art.Tf. in the telephone wagon the carrying straps are to be removed and also stored in the wagon. The main components of the Art.Tf. are:
- The handset. Its microphone capsule is replaceable. It must be handled carefully to avoid wire breaks in the cord. To make a call, it is held in the left hand. To speak, press the talk button and hold the handset vertically so that the carbon grains of the microphone are not stored on one side, which would result in the interruption of the battery power. The buzzer button is only to be pressed when calling with the buzzer and for any transmission of Morse code.
- The headset is housed in the side compartment together with a screwdriver. It is constructed the same as the handset telephone. With the help of the call trumpet, it can be used to establish a connection. The telephone capsule is interchangeable with that of the handset. The headset is strapped to the right ear, cord down.
- The battery is housed in the insert box.
- The induction coil. Its primary winding is switched into the microphone circuit by pressing the talk or buzzer button. The secondary winding is connected directly to the outside line terminals through the headset and handset telephone.
- The buzzer is a Siemens buzzer.
- Two capacitors. One is built into the buzzer circuit and prevents sparking at the buzzer breaker which would result in gradual burning out.
- Two surge fuses.
Beneath the buzzer a wrench for buzzer adjustment is stored.
Ready to use.
Electrical- and wiring-diagram.
The handset has been updated from it's original form (see Zerlegbares Telephon) to use more modern RX and TX elements.
The cord connections are color coded.
On the left the binding post to connect the battery minus (Battery cable pushed through hole from backside).
Right of it the 6 handset cord connectors (color coded).
Beneath the capacitors (updated in 1935).
On the right side of the partition wall the coil and the lightning arrestors (both updated in 1935).
Left of the partition wall the Siemens-Summer (Siemens type buzzer).
Right of it the battery compartment.
The numbers on the top panel side I assume are a Siemens Serial-number (281413), "1913" indicates the year of development or make, maybe also used as model number.
The empty box.
The handset is stored in the lid and hold by a bracket.
The body goes into the right compartment.
The left compartment is padded with a kind of felt, it is for storing the headset and the screwdriver.
All ready to store.
Ready for transport.
All Art.Tf. are marked with a serial/inventory number (here 187) and the letter A.
A single captive screw holds the body in the box.
The old type Swiss spelling alphabet is added to the front of the box.
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