# Security Keypads On Doors

**URL:** <https://boards.straightdope.com/t/security-keypads-on-doors/190013>\
**Category:** Factual Questions\
**Created:** [July 21, 2003, 9:33pm UTC](https://boards.straightdope.com/t/security-keypads-on-doors/190013 "2003-07-21T21:33:58Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Scruloose](https://avatars.discourse-cdn.com/v4/letter/s/e68b1a/32.png) [@Scruloose](https://boards.straightdope.com/u/Scruloose)\
**Post date:** [July 21, 2003, 9:33pm UTC](https://boards.straightdope.com/t/security-keypads-on-doors/190013/1 "2003-07-21T21:33:58Z")

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If you look at [this](http://www.keyless.com/lockedout.jpg) keyless entry system, you’ll notice two sets of numbers per button. Why is this? Perhaps I’m missing something, but it seems to me that no matter how many numbers you put on a button, the number of possible combinations remains with the number of buttons, and how many digits in the combo, not the number of numbers on a single button. Does that make sense? Why the two numbers per button?  
PS- Hi Rob!

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**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\
**Post date:** [July 21, 2003, 9:36pm UTC](https://boards.straightdope.com/t/security-keypads-on-doors/190013/2 "2003-07-21T21:36:55Z")

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Yep. They did not have room to fit ten buttons (or they didn’t want to.) But most people who use numeric PIN numbers and such have a favorite number and expect all ten numbers to be available. So they put two numbers on each button.

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**Author:** ![fluoextinchcl](https://avatars.discourse-cdn.com/v4/letter/f/b2d939/32.png) [@fluoextinchcl](https://boards.straightdope.com/u/fluoextinchcl)\
**Post date:** [July 21, 2003, 10:06pm UTC](https://boards.straightdope.com/t/security-keypads-on-doors/190013/3 "2003-07-21T22:06:13Z")

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I haven’t got a Ford Crown Victoria owners manual handy, but I remember reading one for a rental car. If I remember what I read correctly, if you want the other digit you press the button two times.

The PIN 1450 would be firstbutton secondbutton secondbutton thirdbutton lastbutton lastbutton.

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**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\
**Post date:** [July 21, 2003, 10:13pm UTC](https://boards.straightdope.com/t/security-keypads-on-doors/190013/4 "2003-07-21T22:13:11Z")

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That’s interesting, **fluoextinchcl** , I haven’t met any car door keypads that work like that. (But I’ve never driven a Crown Vic).