The XCL8010A is the Controller Module of the Honeywell Excel 800 Control System, used to communicate with Panel Bus and LonWorks Bus I/O Modules for HVAC system control.
The 100-34702-001 is a genuine Honeywell Vertical Bus Driver component used in industrial automation systems like the Honeywell SIS, HC900, and C300 systems.
The S7999B is a system display module used in Honeywell burner/boiler control systems (as part of the ControLinks and 7800 Series burner control systems).