Honeywell CIU 888 Configuration Manual page 203

FIGURE C-8
Part No.: 4417584_Rev12
Appendix C - Redundancy
At CIU 888 level, Modbus maps are created with Unique Unit ID which
can be configured in Modbus TCP/IP Client host systems. This way,
each configured map can be accessed in any Modbus TCP/IP ports.
Modbus TCP host port redundancy with redundant CIU 888s and data synchronization
between host systems
Configuration Manual
CIU 888 C - 17