It is not widely understood that these connector types are mechanically intermateable; meaning, SMA, 3.5-mm, and 2.92-mm connectors, of good quality and in good condition, will inter-mate across connector families without damage. But what are the electrical ramifi cations of inter-mating of these connector types? Can they be used interchangeably without an appreciable difference in performance, i.e. will a significant impedance discontinuity occur when mixing types? Were they intended to be inter-mated in the first place? To properly answer these questions calls for a brief examination of the history and motivations behind these connectors.