The interactive messaging system of the present invention provides for an interactive communication process between users, both senders and recipients. The method includes filling discrete regions of a disk-shaped die with ferromagnetic and non-ferromagnetic powder metals, compacting to powders, and sintering the compacted powders. The simplified attachingdetaching mechanism 32 for the production line includes a locking plate 34 for locking the second fitted portion 21 and a drive-out member 35 for allowing the drive-out member 35 to rise and set by being engaged with the locking plate 34. However, if the quality is lower than predefined, the data transmission to a wireless section is suppressed to avoid a signal transmission that cannot effectively be used at a receiving station, decrease the average transmission power, and reduce the interference with the other communications. At least one of the buried bit lines is orthogonal to at least one of the vertical gate electrodes of the vertical transistors. The MIMO processing applies a MIMO matrix to the first input signal and the second input signal.