Hi ... not sure if you got a reply on this yet ... from what I could figure out, by setting the unit code on the DS7000, it allows to trigger the "security light" on the Remote Control (Model SH624) to activate the module you have set accordingly. So ... on the remote control, you have access to 5 modules: units 1-4 and a selected module as noted on the Security console ... in my case I selected "6" to turn on "A6" wall switch when I press the "Security Light" on the Remote Control. Refer to owners manual "Page 7".
If you are aware of other uses for the unit code on the DS7000, please let me know, as I'm trying to figure out the relationship between AHP (Active Home Professional) selecting module "DS7000" and then trying to figure out what I set as the house/unit code and how I could use this further.