I moved into an apartment complex where the key is both unique to each apartment door, but every key can open the front door, how are both possible?

Question

I moved into an apartment complex where the key is both unique to each apartment door, but every key can open the front door, how are both possible?

In: 986

Answer 1

Others have explained the “how”, I just wanted to add that this is incredibly common.
And I’d be willing to bet the super has a master key that opens all the doors, internal and external, for emergencies.

Our business has “tiered” keys. Some only give access to your own office, supply closet.
Some give access to offices of anyone equivalent or below you (so, managers can cross cover paperwork, and access workspaces for folks they supervise)
And some open every door in the building.
They’re numbered, the lower the number the more you’ve got access to.

Answer 2

Is called Maison keying. I do not and have not seen it very often in my area. Mostly in campus Dorms. That have multiple rooms that share a common entry door.

Answer 3

Is called Maison keying. I do not and have not seen it very often in my area. Mostly in campus Dorms. That have multiple rooms that share a common entry door.

Answer 4

Is called Maison keying. I do not and have not seen it very often in my area. Mostly in campus Dorms. That have multiple rooms that share a common entry door.