I finally found it out now that I got some more prototypes

Proto 1 the LTC had one side dead and thus the receive was ‘limping’ as typically happens with 485 when one side was dead – that fact sent me on a goose chase with

Proto 2 where both Y and Z were beautiful and I rummaged and rummaged till I got suspicious and located another scope probe and found that Y and Z were in phase (not differential)

Proto 3 was dead – oh well

Proto 4 both Y and Z were beautiful and differential, still it did not work, I read and read and finally found out that LT and B & B electronics do not agree whether A or B is the positive node, reversed the wires and it works now.

As I have often claimed: Murphy was an optimist

Erik

PS other work has been going on, this affair did not take all the time for 3 days.