# Bar Code Info?

**URL:** <https://boards.straightdope.com/t/bar-code-info/49667>\
**Category:** Factual Questions\
**Created:** [January 12, 2001, 7:16am UTC](https://boards.straightdope.com/t/bar-code-info/49667 "2001-01-12T07:16:39Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![OliverTwistofLime](https://avatars.discourse-cdn.com/v4/letter/o/b487fb/32.png) [@OliverTwistofLime](https://boards.straightdope.com/u/OliverTwistofLime)\
**Post date:** [January 12, 2001, 7:16am UTC](https://boards.straightdope.com/t/bar-code-info/49667/1 "2001-01-12T07:16:39Z")

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On business reply evelopes enclosed in numerous letters I receive, what information is present in the bar code underneath the address? Some of my associates who send these envelopes back in the mail empty to increase the expenses of the bank or insurance co. wonder if the bar code has specifics about the receiver of the initial mail.

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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:** [January 12, 2001, 7:57am UTC](https://boards.straightdope.com/t/bar-code-info/49667/2 "2001-01-12T07:57:46Z")

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The bar code has information about where the letter is going; usually it encodes the ZIP+4 information, though there could be other info too (like the postage rate).

Bar codes are not encrypted, they’re basically just a special font. If you’re particularly paranoid, get a barcode reader and find out what it says.

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**Author:** ![manhattan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/manhattan/32/7_2.png) [@manhattan](https://boards.straightdope.com/u/manhattan)\
**Post date:** [January 12, 2001, 7:45pm UTC](https://boards.straightdope.com/t/bar-code-info/49667/3 "2001-01-12T19:45:09Z")

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**Cecil Adams** on [postal bar codes](http://www.straightdope.com/classics/a3_383.html).

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**Author:** ![mrblue92](https://avatars.discourse-cdn.com/v4/letter/m/5daacb/32.png) [@mrblue92](https://boards.straightdope.com/u/mrblue92)\
**Post date:** [January 12, 2001, 8:55pm UTC](https://boards.straightdope.com/t/bar-code-info/49667/4 "2001-01-12T20:55:00Z")

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> [@](#):
>
> If you’re particularly paranoid, get a barcode reader and find out what it says.

Just make sure you get the right kind. There are quite a few different types of barcodes and readers, and they are not necessarily interchangeable. You won’t be able to go down to the local grocery store and run your letter over the scanner. I don’t recall what symbology the USPS uses, but it’s a pretty good bet it’s not UPC.

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**Author:** ![OliverTwistofLime](https://avatars.discourse-cdn.com/v4/letter/o/b487fb/32.png) [@OliverTwistofLime](https://boards.straightdope.com/u/OliverTwistofLime)\
**Post date:** [January 12, 2001, 10:21pm UTC](https://boards.straightdope.com/t/bar-code-info/49667/5 "2001-01-12T22:21:58Z")

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manhattan: thanks for the link. It appears that I’m 10 yrs late asking the same question that Cecil already answered.