The aggregation technique, dedicated to two-terminal series-parallel graphs (or TTSP-graphs) and introduced lately to solve the minimum piecewise linear cost tension problem, is adapted here to solve the minimum binary cost tension problem (or BCT problem). Even on TTSP-graphs, the BCT problem has been proved to be NP-complete. As far as we know, the aggregation is the only algorithm, with mixed integer programming, proposed to solve exactly the BCT problem on TTSP-graphs. A comparison of the efficiency of both methods is presented here.