A plug connector, comprising a) a first plug connector part and a second plug connector part, wherein one of the plug connector parts is formed as a plug part (1, 101) and one of the plug connector parts is formed as a socket part (4, 104), which parts respectively comprise a housing (2, 102; 5, 105) and contacts to be interconnected, preferably electrical contacts and/or optical waveguide contacts (3, 103), b) a coding device (9, 109) having two corresponding coding elements (7, 8, 107,108), c) wherein one of the coding elements (7, 107, 8, 108) is to be arranged on the one plug connector part and the other of the coding elements (8, 108, 7, 107) on the other plug connector part, d) wherein the coding elements (7, 8; 107, 108) are pre-mountable as a premountable unit on at least one of the plug connector parts (1, 104), characterized in that e) the respective other plug connector part (4, 101) is formed in such a way that, on the occasion of the first purely axial plugging together of the two plug connector parts, one of the two coding elements (8, 108) becomes fixed thereto, so that said coding element (8; 108), after the first separation solely by axial pulling apart of the plug connector parts plugged together for the first time, remains disposed on said other plug connector part (4, 104), f) wherein the other coding element (7, 107) comprises spring-loaded leg members (15, 16) with projections (17, 18), which are formed and configured in such a way that the other coding element (7, 107) can be latched rotatably and in different rotational positions in a receiving contour of the one plug connector part (1, 104). a) a first plug connector part and a second plug connector part, wherein one of the plug connector parts is formed as a plug part (1, 101) and one of the plug connector parts is formed as a socket part (4, 104), which parts respectively comprise a housing (2, 102; 5, 105) and contacts to be interconnected, preferably electrical contacts and/or optical waveguide contacts (3, 103), b) a coding device (9, 109) having two corresponding coding elements (7, 8, 107,108), c) wherein one of the coding elements (7, 107, 8, 108) is to be arranged on the one plug connector part and the other of the coding elements (8, 108, 7, 107) on the other plug connector part, d) wherein the coding elements (7, 8; 107, 108) are pre-mountable as a premountable unit on at least one of the plug connector parts (1, 104), e) the respective other plug connector part (4, 101) is formed in such a way that, on the occasion of the first purely axial plugging together of the two plug connector parts, one of the two coding elements (8, 108) becomes fixed thereto, so that said coding element (8; 108), after the first separation solely by axial pulling apart of the plug connector parts plugged together for the first time, remains disposed on said other plug connector part (4, 104), f) wherein the other coding element (7, 107) comprises spring-loaded leg members (15, 16) with projections (17, 18), which are formed and configured in such a way that the other coding element (7, 107) can be latched rotatably and in different rotational positions in a receiving contour of the one plug connector part (1, 104).