1941 Signals film
 

Scenes of training, the field telephones are WW1 era , The small wireless sets are W.S. 108 .
https://www.youtube.com/watch?v=XO_W...6jIhiFW1bMfTuU

108
 

The Ws108 Mk2 was considered to be a complete dud , they tried it out during the Papuan / Kokoda battles and it failed miserably due to the cotton insulation failing in the humid climate. The later version was made with the then new PVC insulation.