| The difficulty with these sBus expansion boxes is that they don't work
| RELIABLY, they may appear to work but under heavy load (and maybe
| environmental stress) they fail to correctly forward bus cycles to the
| slave bus.  They are playing with the tolerance margins in order to work
| at all.

There are 2 different types of SBus expander boxes.  Some are merely an
extension of the SBus and are rather flaky.  Others, like the Sun models,
have an additional set of data buffers to provide an SBus-SBus bridge.  
These are reliable, but much slower due to the additional delays.

Eduardo