Episode 8 - Poste téléphonique pour l'essai des lignes, 1941


This french linemans instrument is made in 1941 by the Association des ouvriers en instruments de précision, a french workers cooperative which specialised in telecommunications equipment manufacturing (once the world's biggest cooperative outside of USSR, operating from 1896 until 2003). The instrument is a french P.T.T. standard design for linemen portable instruments. It has been made by different french P.T.T. outfitters. The models type 292-60 is also engraved on the wooden body, along with Propriété de l'état which indicates that it is an instrument officially issued to the french P.T.T.

The instrument comes in a leather pouch or in a metal box. This one has a metal box. The main body is made of wood with sliding lids. Beneath one lid is the battery compartment which takes two 1,5V dry elements of a french special size (still used in SNCF instruments up to the 90ies). The other lid houses the instruments electromechanical parts: the small generator and a single bell ringer which shares it's coil setup with the main voice current coil. On one of the lids an electrical diagram on a metal plate is fitted.

Unique feature

Compact length adjustable handset. The handset is constructed similar to french early century handsets with the microphone mounted behind the speaker and a long tube as microphone sound channel. The tube's length is adjustable. It has to be minimised for storage.



Partly disassembled.

Ready to pack.

In the box.

Ready for transport.

Wiring and electrical diagram.

Manufacturer label. Association des ouvriers en instruments de précision

Propriété de l'état engraved on wood body, indicating that it is an instrument officially issued to the french P.T.T.

The type designation 292-60 engraved on wood body.

Top of body with the generator handle removed. The handset is stored inside the groove and held by the metal bracket and the small wooden lever.

Inside the body a compact generator and the single bell ringer which uses a coil combined with the voice coil. On the right the five lead handset connector.

The battery box with the two battery connectors.

Modern battery replacement.

French dry elements (Type R25-0,2, 1,1V) taken from an SNCF field phone. This size seems to match for different french field instruments. I could not find any information french type element sizes, please comment if you know something.

The metal case.

The empty handset.

The adjustable handset. The tube can be slid inside the guides mounted to the handset capsule.

TX element front.

TX element back. Made in 1947.

RX front.

Backside of the RX element. The P.T.T. mechanism brakes the RX circuit on the top right and closes the TX circuit by pressing the contact in front of the red pulley to the back of the RX element.


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