Anyone know how these old cam switch lock alarms used to work?

I’m following this too because I’m curious. But those locks don’t look too secure… seems more like a deterrent than real security.

It’s pretty basic. You turn the key one way to arm the alarm, and the other way to disarm it. Not much else to it.

It might have actually been for something other than an alarm. Key switches like these are used for all sorts of things where you want control outside but don’t want people messing with it. Computers even had them for a while: https://old.reddit.com/r/retrobattlestations/comments/jbwpsg/my_favourite_pc_amd_386dx40/

I should be clearer… I’m more interested in how these worked as an alarm, like the history and purpose behind them. Was this from before digital keypads became popular? What era are we talking about here?

Would there have been sensors in the door or frame that set off a siren when opened? Could someone arm it from inside the house?

Also, was this meant to be a local alarm or connected to an external service like a security company? Who would typically install these systems?

@Unclewaffl3s
Those look like standard keyswitches. They’ve been used forever and still pop up today in a lot of systems.

There might’ve been sensors in the door frame that completed a circuit, but it’s tough to know exactly what they did without seeing more details.

I’d guess there was something inside too—maybe a keypad or more switches—but it could’ve been ripped out during a renovation. You might find some info if you dig around in the wiring or any control box left in the house.

Can’t tell much from the second photo, though. Looks like it’s all painted over.

@Moses
Thanks! The house was remodeled in the last 10 years, so maybe the interior parts were removed during that.

Unclewaffl3s said:
@Moses
Thanks! The house was remodeled in the last 10 years, so maybe the interior parts were removed during that.

I wonder why there’s two switches outside next to the door… maybe one ran to those doorbell-looking things?

Edit: Actually, maybe not. Looks like there’s another door to the right, so probably one switch for each.

Edit again: The more I think about it, this could’ve been something very simple if there wasn’t an alarm system in the building. Maybe each door had a bell that would go off as an alert if not turned off? Just guessing here.

@Moses
Yeah, my door is on the left, and the neighbor’s door is the one in the frame. My door used to open from the right side, so the switch lock was right next to the doorknob and deadbolt. But the switch on my neighbor’s door is actually on the hinge side, and there’s a third door with a similar setup.

The doorbell and speaker-looking things are for the neighbor’s door, by the way. Mine’s out of frame on a separate wall.

@Unclewaffl3s
Got it! That makes sense now. Looks like that second picture might just be the wiring for the keyswitch on the other side… kind of an odd placement, but still, pretty neat! If you’re up for it, you could try tracing that wiring… but be prepared, it might lead to even more questions!

@Moses
Haha, that sounds like a rabbit hole waiting to happen!

What’s that black thing above the doorbell button? Is it a light? Or maybe some sort of voice tube?

Julius said:
What’s that black thing above the doorbell button? Is it a light? Or maybe some sort of voice tube?

I think so! It goes up to the open side of the stairwell. If it was ever used, it probably connected up to the banister at the top of the stairs. Just one of those cool Victorian features from the 1880s!

@Unclewaffl3s
That’s what I love about old houses! You never know what odd, unique features you’ll find. We’ve all seen those intercoms in houses from the ‘80s and ‘90s, and these days there’s all the smart tech like Ring. But it’s pretty cool to see something that’s much older and still had some sort of communication function.