In Basic Terms:
Press down on the lever and deadbolt and lever latch retract simultaneously.
You may have heard of interconnected locks before, also known as emergency egress locks. These special handlesets are designed to easily unlock the door. Basically it's a lock where the deadbolt and knob (or lever) latch are linked with a device called and interconnect device. An interconnect device is an internal mechanism that deactivates the deadbolt lock when you turn the door knob/lever from the inside to open the door. There are a couple different styles available so be sure to verify how your existing door is prepped before you order so you can be sure it will fit correctly (to find out more information about two different types of interconnected locks click here and read the information given at the bottom of this page).
It's important, in some applications, that their locks are Fire Marshall Approved. Which basically means that occupants can exit the building easily in case of emergency. With these interconnect locks or emergency egress locks, you can easily open the door in a single action making it really convenient when exiting and that's especially important if there were some kind of an emergency. It's designed to open even if the door is locked!
*NOTE: These Interconnected locks meet the requirements of most Fire Marshals, but the user may need to check with their own local authority to verify.
Interconnect locks have been uses in hospitals, group homes, apartment buildings and other public access places, but you could easily use them for your own home if you wish. It does make for an easy exit.
You can find a ton more information on emergency egress (interconnected) locks here.