Zone 3 Recommendation
The Zone 3 connector in the MicroTCA.4 standard connects the Advanced-Mezzanine Card (AMC) module and the Rear-Transition Module (RTM). MicroTCA.4 defines the management on the Zone 3 connector and provides enough freedom to the designers to use an application-specific pin assignment for an AMC and RTM pair.
To improve the compatibility and modularity of AMC and RTM boards we present a classification recommendation of the Zone 3 connector pin assignment for the MicroTCA.4 standard for different classes of applications. This implies a zone description, electrical specification, electrical protection sequence, electronic keying and grounding and shielding options.

Zone 3 Pin Assignment Recommendation for Analog Applications for AMC/RTM Boards in the MicroTCA.4 standard (Release Rev.A.4 - 26/08/2014 approved by the BoF Group 1)

Zone 3 Pin Assignment Recommendation for Digital Applications for AMC/RTM Boards in the MicroTCA.4 standard (Release Rev.A.3 - 21/03/2013 approved by the BoF Group 1)
To guarantee and maintain the AMC and RTM compatibility of previous, existing and future products only minor changes of released classes can be requested to the BoF Group 1 convener. The introduction of new fields of classes is supported by the BoF Group 1, contact person is the convener.