Abstract: An electronics module assembly for detachably retaining a pair of electronic sub-modules in a single slot of a chassis. A host module of the electronics module assembly is configured to be detachably received and retained in a slot of the chassis. The host module has a height corresponding with a height of the slot of the chassis. A pair of sub-modules are configured to be detachably received and retained in the host module. The combined height of the sub-modules is no greater than the height dimension of the slot of the chassis. Therefore, where there was once only room for one electronics module in a single slot of the chassis, a pair of sub-modules with the host module may now be utilized in the single slot of the chassis.