Last night ACP threw the "Bad input string" error - but there is a bit of new information... the only thing connected to ACP was the dome. The TIM unit was not connected.
I kinda wish I could see the string that was sent! By the process of elimination it is coming from MaxDome- but what is it saying?! Perhaps there is noise and the information is garbled?
(desperation theories...).

Anyway, just an update.