In this paper, a Schwarz heterogeneous domain decomposition method (DDM) is used to co-simulate an RLC electrical circuit where a part of the domain is modeled with Electro-Magnetic Transients (EMT) modeling and the other part with dynamic phasor (TS) modeling. Domain partitioning is not based on cutting at transmission lines which introduces a physical delay on the dynamics of the solution, as is usually done, but only on connectivity considerations. We show the convergence property of the homogeneous DDM EMT-EMT and TS-TS and of the heterogeneous DDM TS-EMT, with and without overlap and we use the pure linear divergence/convergence of the method to accelerate it toward the searched solution with the Aitken's acceleration of the convergence technique.