This paper focuses on the derivation of valid contracted graphs (CGs) with ternary links T and quaternary links Q using characteristic strings for type synthesis of parallel mechanisms. First, some concepts on the associated linkage, the CGs, and characteristic strings are explained, and the numbers of vertices and edges for constructing CGs with T and Q are solved. Second, the relative criteria are determined for representing CGs with T and Q and identifying their isomorphism using characteristic strings. Third, some simple CGs with T and Q are represented by the characteristic strings and their isomorphic/invalid CGs are identified. Finally, many complex, valid CGs with T and Q are derived by characteristic strings.