An electrical connector assembly can include a plug connector mountable to a planar substrate and a receptacle connector configured to receive a plurality of cables and that can mate with the plug connector. The plug connector may include a first inline terminal row and a second inline terminal row exposed on a mounting face to conductively contact the planar substrate. The receptacle connector can include a plurality of terminals having termination ends aligned in common wafer plane that can be conductively terminated with the plurality of cables. The plug connector and the electrical connector are configured to establish electrical channels from the termination ends coplanar with the common wafer plan to the first and second inline terminal rows.