Fullerphones developed in World War 1 had invariably a built-in field telephone option
which led in some cases to the belief that this was also secure.
In the late thirties new models were developed which were mechanically simplified,
using a replaceable buzzer-chopper, and the field telephone option was omitted. In
Canada, Germany, Finland and France the mechanical buzzer was replaced by an electronic
Posted in this section is a variety of different models and patterns of Fullerphones.
The use of British Fullerphones and manufacture of similar instruments in other countries,
notably France, Australia, Italy, Portugal, Finland, Germany, Canada, USA and Holland
In Germany and Holland the Fullerphone was called 'Geheim Telegraaf' (Secret or Secure
Telegraph). Later developed electronic versions are dealt with in a separate section.