Powering-up the lights in a old piece of technology
March 30, 2018 8:33 AM   Subscribe

I have a touch panel from a 1991 AT&T home security system complete with wiring harness and supposedly in good working order. I'd like to somehow use common household batteries as a power source to illuminate the panel's lights. Is this possible?
posted by Jamesonian to Technology (4 answers total) 1 user marked this as a favorite
 
Probably. Do you have a pic of the circuit side of the panel?
posted by zippy at 8:58 AM on March 30, 2018


Check out the "battery and power supply considerations" section of the AT&T 8300 Installation Manual.

You need something that gives 12v nominal (looks like it was set up to use a lead acid battery like a car battery as its backup) . That could probably be two 6v lantern batteries in series[1], or depening on your run time requirements, 8 AA batteries in series. The internets suggest that those are 21000 to 26000 mAh (milliamp hours) each[2].

So if you total up the current usage in milliamps of the various portions of the alarm system you want to hook up, and divide the available supply by that number, you'll get the number of hours of runtime (mAh/mA = h).


[1] "series" means that you connect the negative terminal of one battery to the positive terminal of the other battery, that way from the unconnected negative terminal to the unconnected positive terminal you get the sum of the voltages of the batteries.

[2] when you hook up batteries in series, you get the same amphour (milliamphour) capacity at higher voltage. When you hook them up in parallel, you get more amphour capacity at the same voltage. So if you hooked up two lantern batteries in series you'd get 21Ah to 26Ah at 12v. If you take another two batteries, hook those up in series, but then tie the free plus and minus together, you'd get 42Ah to 52Ah capacity.
posted by straw at 9:20 AM on March 30, 2018 [1 favorite]


Response by poster: @zippy All I can see from the outside are the colored wires of the wiring harness. Red, green, yellow, black, etc. My guess is that power goes thru the red?

@straw To be clear, I don't want to run a whole security system! I don't have such a system. All I have is the control panel for one. It has keys the illuminate from inside, so I'd like to power those lights so that it looks like a working panel but it won't be connected to a system.
posted by Jamesonian at 4:05 PM on March 30, 2018


Best answer: I can't find definitive specs on just the control panel, but from the doc I linked it looks like the control panel gets power, common (aka ground or minus), and two signal lines. I don't know for sure, but I'd make a good guess that 12v on the power+common line would give you those lights.
posted by straw at 4:40 PM on March 30, 2018


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