A portable telephone for CB (central battery) networks. Wood box and metal chassis are constructed similar to a Streckenfernsprecher OB33. These instruments were probably used in some "wide area" industrial environment like a power plant, a steal mill or similar.
The instrument was made by Siemens & Halske in 1939.
Product description from the Siemens & Halske telecom products catalogue "F-Sammelliste 1939" [1]:
Tragbarer ZB-Fernsprecher in Eichenholzgehäuse mit abnehmbarem Tragriemen, Handapparat mit Handgriffeinschaltung, mit Wechselstromwecker 600 Ohm, für Leitungsanschluss an innen angeordneten Kordelklemmen.
(Portable CB telephone in oak housing with detachable carrying strap, handset with switch, with 600 ohms ringer, for connection to binding posts arranged on the inside.)
Disassembled.
Wiring diagram inside top lid.
Self made electrical diagram.
Page from Siemens & Halske Catalog of 1939 [1].
Product. No. (Listen-.Nr.) 406 090.
Price was 114.- "Reichsmark" which would correspond to roughly ~770 Euros in 2023 [2].
(Note that the image on the left of the text is not this instrument, it is a LB instrument with product no. 406 089)
Disassembled handset.
The handset is based on the post type 1928 and uses the same handset switch as handsets of the FFsp 33.
The chassis is quite empty as it uses the basic construction of an LB device but does not need the magneto.
It's just ringer, coil, capacitor.
From the back.
Bottom.
Siemens & Halske product id: "Fg.trgb.8a".
The "U7" in mfg. code 5U7 points to a mfg. date of July 1939.
The Mfg place id "5" is unknown.
Capacitor is also S&H and made in 1939.
Coil, a standard 3 windings & 1 bifilar winding coil for anti-sidetone circuit setups.
Also S&H made.
Neatly arranged to assemble.
Empty box.
Ready to use.
Ready for transport.
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