Abstract: A cardiac pacer employing the connector system disclosed herein is usable with either a unipolar lead or a bipolar lead provided with a plug at the proximal end having an extending pin portion to which a distal stimulating electrode is electrically connected. In the case of a bipolar electrode, an annular ring is provided on the plug to which the reference or indifferent electrode is connected. Respective clamping means are provided for establishing electrical connections to the pin and the annular ring, if present. A bridging means is provided for utilizing the pacer case as a reference potential when a unipolar lead is being used.