A pluggable connector that includes a connector housing having mating and loading ends and a longitudinal axis extending therebetween. The connector housing includes an insert cavity that opens to the mating end. The pluggable connector also includes a plug insert that is disposed within the insert cavity. The plug insert has an air core that extends in a direction along the longitudinal axis. The pluggable connector also including first and second differential pairs that extend along the longitudinal axis through the plug insert. Each of the first and second differential pairs includes two mating contacts that extend parallel to each other. The air core is located directly between the first and second differential pairs to control the electromagnetic coupling between the first and second differential pairs.