Can someone explain how this old lock system works?

[Wolfe]

Yeah its completly intentional. Think of it as a multi functioning door lock.You either have the choice of leaving it open and unsecure or if you were to have a business or a apartment building you could make it a one way door needing the key to enter back in. Being in the real estate business and rehabing hundreds of homes ive come across these in about every older (typically around the 50's) home/apartments/business but not always on the front door.

[Lorek]

I've seen a couple of these as well, from what I have read the original function of the buttons was an added security measure to prevent the outside lock from being used after everyone had gone to bed at night. Effectively keeping the house safe and secure from the outside short of forced entry. There were several later models that didn't require buttons that did the same thing with a thumbturn or latch.

[digital_blue]

Alright. Mystery solved.

Indeed, HeadHunter was correct. The latch is, in fact, operated by turning the key in the opposite direction. Turns out when I sent my friend in the hall the first time it "never occurred to him to turn the key the other way".

Man.. I need some new friends. j/k

Anyway... I was there last night and tried it for myself and found that, indeed, it works like HH described in the first place.

Cheers guys,

db