A connector and circuit board assembly includes terminals in a connector that are mounted to vias in a circuit board. Signal and ground terminals are thus coupled to signal traces and ground planes in the circuit board. Additional pinning vias that are aligned with the ground vias may be provided in a circuit board to help improve electrical performance at the interface between the terminals in the connector and the signal traces in the circuit board. A signal collar may allow pairs of signal traces to be split and routed around two difference sides of a via before rejoining while maintaining close electrical proximity that provides for relatively consistent electrical coupling between the traces in the pair of signal traces.