The "Armeetelefon Modell 1947" and the "Feldtelefon Modell 1947" are only slightly updated, nearly identical replacements for their predecessors ATf 1932 and FTf 1941. The ATf update was again developed by Albiswerk Zürich (Swiss Siemens subsidiary, also licensed to Autophon, Hasler and Zellweger), and the FTf also again by Autophon A.G. Solothurn.
The mechanical setup is identical to the predecessors, the electrical update consisted in 4 points (from the "Armeetelefon 32 and 47" handbook [2], but identically true for the FTf):
The formerly used Albiswerk buzzer which included the simple P/S speech coil circuit was replace by an anti-sidetone four winding speech coil setup. Another above not mentioned change is that although the Handset body is the same the RX/TX covers have been adapted to fit with newer PTT type 46 capsules compared to the type 31 used in the predecessors.
For both cases the enclosure is identical to the respective second generation enclosure of the predecessor, so for the ATf the chassis is painted black and the wood box clear lacquered, for the FTf the chassis includes the metallic lid support with the better lid open lock mechanism.
Of the FTf 47 only ~500 and of the ATf 47 ~4000 were made [1], as they were soon replaced by the FTf 50 and ATf 53. The serial/inventory numbering was not restarted but more or less continued on it's predecessors numbers, ATf 47 seem to start at ~15000 and FTf 47 at ~1500.
Disassembled.
ATf 47 diagram.
Mostly identical setup to ATf 32 but with an anti-sidetone coil circuit instead of a combined buzzer/coil and with a line-test button.
Inside the same mechanical setup, where the buzzer module was now the coil is mounted (on the right).
The line-test button (Bilingual label: "Ltg. prüfen, Essai de ligne") where the buzzer button was in the ATf 32.
Ready to use.
This one with Serno#16666 was made by Albiswerk in 1950.
The ATf 47 seem to have been numbered from ~15000 to ~20000 (lowest I have has #15164 and highest #19175).
Packed.
Ready for transport.
At first sight indistinguishable from an ATf 1932.
FTf 47 electrical diagram.
Mostly identical setup to FTf 41 but with an anti-sidetone coil circuit instead of a combined buzzer/coil.
FTf 47 wiring diagram.
Inside the same mechanical setup, where the buzzer module was now the coil is mounted (on the right).
Made by Autophon in 1948.
Strangely one of the capacitors has a date code of 41, either during mfg. or with a later repair apparently old stock was used.
Ready to use.
Packed.
Ready for transport.
At first sight indistinguishable from an FTf 1941.
Handsets from back to front: ATf 32, ATf 47, FTf 41, FTf 47.
ATf handsets, in the back the 1932 in the fron the 1947.
The base is identical.
The 1932 uses capsules of PTT type 1931 handsets.
The 1947 has covers adapted to fit capsules from PTT typ 1946 handsets.
FTf handsets, in the back the 1932 in the fron the 1947.
The base is identical, but the 1947 has no buzzer button.
The 1932 uses capsules of PTT type 1931 handsets.
The 1947 has covers adapted to fit capsules from PTT typ 1946 handsets.
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