udata_acs
-nmractrl res 1 ; byte 4: state relevant to NMRA control
-transmitbit res 1 ; bit 7: 0/1 bit currently being transmitted
-nextaction res 1 ; bit 0: change polarity on next interrupt y/n
+nmractrl res 1 ; state relevant to NMRA control
+transmitbit equ 7 ; bit 7: 0/1 bit currently being transmitted
+nextaction equ 6 ; bit 6: change polarity on next interrupt y/n
fromserial res 1 ; from-serial buffer location (in buffer bank)
totrack res 1 ; to-track buffer location (in buffer bank)