The 340 Casemates
Topped with 'cloches', they helped ward off foe inroads through the line of 'ouvrages', protecting the latter's flanks. They stood guard over the extension area from 'La Ferté' to the Channel and on one or two lines along the river Rhine. They were each manned by 25 to 30 soldiers and equipped for self-sufficient operations. They used to be connected by telephone or radio to one another and to neighbouring 'ouvrages', and held the weaponry used for short range coverage fire.