  Dual scattering channel (DSC) schemes naturally extend the transmission line
matrix (TLM) numerical method beyond the lines set up by P.B.JOHNS and
coworkers. Conceptually, DSC schemes retain from TLM the typical formal
splitting of the computed fields into incident and reflected components,
interchanged and scattered between adjacent cells, without yet a need for
transmission lines. They generally admit non trivial cell interface scattering
and so release from a set of modeling limitations to that the classical TLM
method is subject. The elements characterizing DSC schemes are outlined and
illustrated by coupling within a non-orthogonal mesh a model of heat
propagation to a lossy Maxwell field.
