Signal Training Volume III, Pamphlet No. 23, Telephone Sets F Mark I, 1939
From RCSigs.ca
The Signal Training Volume III, Pamphlet No. 23, Telephone Sets Mark I and I*, 1939 was issued by the War Office in October 1939. The pamphlet is 39 pages long and gives a general description of the set, a technical description, working instructions and maintenance and repair instructions.