I wrote:
I just found the solution: Put the SSC SW2-6 in position on to enable interrupts from the SSC. This is a requirement of all the comm programs except ADT and IN#2/PR#2.My SW2-6 was set to off on the recommendation in the ADT manual...
setting SW2-6 to on does not affect ADT which works nicely on 115200 baud still. If someone updates ADT again we should put in a note on this in the manual.
Knut