Honeywell CIU 888 Configuration Manual page 213

Appendix C - Redundancy
as switchover command in CIU 888). Then configure Source and
Destination Address as OUTPUT 1 and download the point to server.
C.12.3.3 Configure Digital Input(Hotstandby Status)
HOTSTANDBYSTATUS is a Digital Input created for getting the
Hotstandby Status of CIU 888. This is associated to the INPUT
controller and the PV Source Address is given as INPUT 1 (where
INPUT indicates the Controller & 1 indicates the Modbus address of the
Hotstandby status of CIU 888).
Part No.: 4417584_Rev12 Configuration Manual
CIU 888 C - 27