An electrical receptacle connector (10) including a one-piece shell (12) affixed to a housing (14) and adapted to be mounted at an input/output port of an apparatus and on a circuit board within a panel. Shell (12) includes a front wall (66) that provides shielding of the mating interface adjacent the panel cutout(s), and an upper wall (62) and a lower wall (64) extending rearwardly from the front wall (66). Retention spring arms (70,94) extend from the upper and lower walls through recesses (34,56) into plug-receiving cavities (32) to engage and retain the mating connector in a mated condition, and ground legs (96) secure the connector to a circuit board. The connector may have a pair of plug-receiving cavities (32) divided by a vertical housing wall (112), and the lower shell wall (64) may comprise two portions (84) each receivable along a slot (60) above a bottom housing wall (54) to be insulated from a circuit board beneath the connector.