An adapter frame assembly is provided for receiving at least a pair of connectors in a stacked array with one connector above another connector at different spacings therebetween. The assembly includes at least a pair of frame structures including at least a top frame structure and a bottom frame structure each including a receptacle for receiving a respective one of the stacked connectors. The top frame structure may be mounted directly on top of the bottom frame structure and, thereby, space the receptacles and the respective connectors at a first spacing therebetween. A spacer is selectively mountable between the frame structures to thereby space the receptacles and the respective connectors at a second, increased spacing therebetween.