An electrical connector assembly includes a receptacle connector (24) having a first non-conductive housing (51) for mounting on a printed circuit board (28) and including a mating receptacle (54). A plurality of board terminals (52) are mounted on the first housing and have tail portions (62) for connection to appropriate circuit traces on the circuit board and contact portions (58,58a) extending into the mating receptacle. A plug connector (22) has a second non-conductive housing (30) including a mating plug portion (30b) for insertion into the mating receptacle of the receptacle connector. A plurality of signal terminals (32) are mounted on the second housing and have contact portions (32b) on the mating plug portion thereof for engaging the contact portions of the board terminals in the mating receptacle when the connectors are mated. The signal terminals include terminating portions (32a) for termination to a plurality of discrete signal conductors (26a). A single metal shell (42) is mounted on the second housing of the plug connector and projects therefrom over the first housing of the receptacle connector to shield the mating interface between the board terminals and the signal terminals when the connectors are mated.