Transmission of images
The 9 February 1907 edition of the French review “L’illustration” gives an account of a lecture presented by Professor Kom on the transmission of photographs by telephone on the Paris-Lyon-Paris circuit (1024km).
On the basis of this process, Frenchman Edouard Belin developed the belinograph in the 1920s, a photograph transmission machine using the telephone or telegraphic network
Portable Belin transmission machine, France, around 1940
Was used uniquely to transmit images, with an average duration of 6 minutes: the photograph for transmission was placed on the cylinder and the operator regulated the balance between black and white on the telephone with the person he was calling.
The cylinder carrying the image rotated in front of a “line by line” reading system, which transmitted the image on the telephonic network by impulses that varied according to the composition of the white, grey and black composing them. The higher the cylinder rotation speed, the lower the image quality on arrival.