Hi, Sorry if this duplicates - I'm reposting since the first message seems to have gone astray. I'm designing an fluid leak alarm system and want to make it expandable by using networked expansion units. I have heard of KEYBUS used by DSC Security Systems, that might be suitable, but can't find any useful info on it anywhere. I have info on ProfiBus and FieldBus, but they look pretty complex. Help anyone? John Lawton