Interconnect - This capability is important because if any interconnect smoke alarm goes off it triggers all of the interconnected smoke alarms. It s required by code.
Hardwired - Smoke and Carbon alarms are hardwired with battery backup in case of power failure. The hardwired capability has a third wire that is used to interconnect all of the smoke & carbom alarms . This is also required by code.
It is battery only - it can NOT be hardwired. (I just installed one that replaced a battery one)
I just installed a complete system and really like it so far, my one concern is the fact that the base siren volume is not adjustable. I don't have a large house and i have pets so when the system alarm is tested it is extremely loud, I wonder if Ring Tech's could make changes possible via updates, that would be great!