The module size selected is the double mid-size module*. The mid-size width allows the maximum possible number of 12 AdvancedMC modules including 2 MCHs** and up to 4 power modules to be accommodated in a 19" wide system.

For the MicroRTM roughly the same space was chosen as for the front module. The MicroTCA.4 system is thus twice as deep as a MicroTCA.0 system. This provides the user with a large amount of space for active logic on the MicroRTM module.

The front panels of the MicroTCA.4 system are borrowed from MicroTCA.1 (Rugged MicroTCA). Accordingly, the modules can be fixed in the system with the special ruggedized screw fitting to prevent their being "pushed out" when the RTM is fitted.

MicroTCA.1 front panels are also used in the RTM area of MicroTCA.4 systems, though rotated through 180°. Thus no new, special front panels are required for the MicroRTM modules; the existing front panels may be used.

The MicroRTM module is linked directly via a connector set in the upper area to the front panel (comparable with zone 3 in AdvancedTCA). Thus no special backplanes are required to loop the signals through from front to rear. Optionally, however, a "Zone 3 backplane" may be used to transfer the RTM signals to other modules.

* Height 150 mm, width 4 HP, depth 180 mm
** MCH = MicroTCA carrier hub