This field phone is somewhat difficult to identify. Based on its components and construction style, I estimate it was manufactured between 1905 and 1915. The company name "C. Schaefer" on the label suggests either the manufacturer or a dealer, as the firm has been in existence since 1889. While the company still operates today, it lacks documentation dating back that far.
The craftsmanship suggests the instrument was made in a workshop setting rather than through industrial production.
I acquired it in the Grison region. The burned-in letters "EW. C" may indicate ownership by "Elektrizitätswerk Churwalden" (Churwalden Power Plant), which operated under that name from 1906 until the 1950s.
The phone features a basic two-winding induction coil, a four-bar magneto, and a 2x750-ohm ringer mounted on a main wooden board, all housed in a wooden box. The handset is composed of a steel frame with wooden handles, a push-to-talk (PTT) switch, a fixed 200-ohm receiver with a wooden earpiece, and a modular transmitter using the "Lorenz" carbon transmitter format.
Pre-renovation
Ready to use
Ready, open (no batteries inserted)
Main board bottom, 2 winding coil, ringer, generator
Main board top, battery leads, bells, line connectors, lightning arrestors, pin to store crank handle
Handset disassembled
Wrong transmitter capsule (ZB = central battery instead of local battery, C.L. D.R.P. is probably C. Lorenz - Deutsche Reichspost) - Fix receiver 2x 100Ohm
C. Schaefer Fournitures électrotechniques en gros Zurich (Label inside lid)
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EW. C - probably EW Churwalden (Powerplant of Churwalden)
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All stowed
Ready for storage
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