  Dual scattering channel (DSC) schemes generalize Johns' TLM algorithm in
replacing transmission lines with abstract scattering channels in terms of
paired distributions. A well known merit of TLM schemes is unconditional
stability, a property that is commonly drawn upon the passivity of linear
transmission line networks. So the question arises, if DSC algorithms remain
stable in a neat sense. It is shown that a large class of alpha-passive
processes are in fact unconditionally stable. The analysis applies to TLM and
DSC schemes alike and includes non-linear situations.
