Electrical connection connector with asymmetrical fastening contact modules and associated locking device

A contact module for an electrical connection connector, comprising:

• a casing delimiting a housing configured to receive at least one contact plate overmoulded in a support,
• said contact plate comprising a first end intended to cooperate with a contact element of an adjacent complementary module, and a second end in the form of a curved contact strip intended to support a printed circuit board,
• said casing comprising a first and a second snap-fit tabs, each snap-fit tab having at least one protruding and inclined bearing surface relative to a longitudinal face of the casing,
• characterised in that:
• the first snap-fit tab is located on a first longitudinal face of the casing and the second snap-fit tab, separate from said first snap-fit tab, is located on an opposite longitudinal face of said casing,
• and in that the bearing surfaces of the snap-fit tabs are arranged in a staggered manner on separate planes positioned at different heights in the inner wall.