Stacked electrical connector assembly

A multi-port connector assembly comprising:

• a unitary insulative housing defining a plurality of cavities arranged in rows and columns in a front portion and a plurality of receiving spaces in a rear portion and in aligned communication with the corresponding cavities in a front-to-back direction, respectively;
• said cavities being arranged in at least two columns;
• plural groups of signal terminals forwardly inserted into the corresponding receiving spaces, respectively;
• said groups being similar to one another.
• at least two grounding terminals each with arms extending into the corresponding receiving spaces, respectively;
• a spacer located behind the housing and defining plural sets of vertical passageways, said plural sets of vertical passageways being arranged in at least two columns corresponding to said at least two columns of the cavities, respectively;
• and
• plural sets of transition contacts located between said plural groups of signal terminals and the spacer, said plural sets of transition contacts being arranged in at least two columns corresponding to said at least two columns of the cavities and said at least two columns of vertical passageways, each set of transition contacts defining horizontal sections mechanically and electrically engaged with the corresponding group of signal terminals, respectively, and vertical sections received in and aligned by the corresponding set of vertical passageways, respectively;
• wherein
• the horizontal sections of the transition contacts in each individual set are similar with one another, while those in different sets in the same column are different from one another under a condition that the transition contacts located in a higher level have longer horizontal sections than those in a lower level wherein each of said cavities includes a circular hole with at least one fastening opening beside said hole, and a plurality of mating ports respectively assembled into the corresponding cavities, and wherein each of mating ports defines a cylindrical neck received in the hole and at least one fastening projection received in the corresponding fastening opening.