Abstract: An automatic main distributing frame (MDF) apparatus for connecting and disconnecting an exchange and a user terminal includes a first-staged matrix board having a plurality of input/output lines, the input/output lines being disposed in a matrix pattern. The MDF apparatus also includes second-staged and third-staged matrix boards having a plurality of input/output lines, the input/output lines also being disposed in matrix patterns. The second-staged matrix board is disposed perpendicular to the first matrix board and the third-staged matrix board is disposed perpendicular to the second matrix board. A center board is disposed between the first-staged matrix board and the second-staged matrix board and between the second-staged matrix board and the third-staged matrix board. The center board, the first-staged matrix board, the second-staged matrix board, and the third-staged matrix board are mutually connected through connectors.