How did First World War field telephones communicate?

Question

I'm thinking of the phones that needed 'winding' to draw electricity from an internal battery. If the phone was connected to a cable, no problem, but how could two field phones communicate without a common cable ? Did they use radio waves not unlike today's mobiles ?

Answer 1

They had to have a cable. However, unlike normal land line phones, they only needed one wire. the return was provided by a ground link.

The alternator that you had to wind was used solely to provide the ringing signal. They needed a battery for amplifying the sound signal.

I find it fascinating that the original telephones like these needed no active electronic components like valves or transistors to amplify the sound signal. The carbon granule microphone changed its resistance in response to sound pressure waves. This resulted in a varying electrical current that had more power than the acoustic soud that generated it.