We propose a generalized <i>T</i> -matrix definition that facilitates the conversion between the <i>S</i>-parameter and <i>T</i>-parameter for multiport networks based on the well understood and mathematically simple two-port relations. This approach generalizes all multiport networks into two cases: balanced and unbalanced. Balanced networks have the same number of entrance and exit ports and are symmetric to the two-port network. Unbalanced networks generate a nonsquare <i>T</i> -matrix and do not have the same number of entrance and exit ports. Through careful selection of the <i>T</i> -matrix, this method extends two-port symmetry to multiport networks and provides an engineering implementable relationship between the <i>S</i>-parameter and <i>T</i>-parameter for multiport networks. This symmetry extension allows a practical means to cascade and de-embed such networks.