friend has a tac20 with a 1091 fault. car runs fine on independent, 2 stop car no hall calls no fire service, advanced Lon manager shows channel A host and LN , nothing shows up under channel B. any ideas would be helpful. he has new LN cards, and lonconfig file, but maybe there is some little thing that he could be missing. 1091 fault indicates LN card not operating properly, ie not receiving data.