Abstract: An indexing mechanism for precision alignment of stacked electronic substrates includes a post associated with a stackable connector and a notch associated with an electronic substrate engaging the connector. The notch is provided to receive the post when the substrate is positioned between two connectors in an assembly thereof. Placement of the post in the notch automatically aligns the electrical contacts of the connector and substrate in their correctly indexed sequence. Connectors can be added to the assembly and additional substrates inserted between any pair of juxtaposed connectors. The indexing mechanism enables precision alignment of any number of substrates in the stacked configuration.