• brianorca@lemmy.world
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      7 months ago

      Probably a serial number for the stamp. In the US, you can even pay online and print your own stamp, and it uses the barcode to track when you use it, so it can’t be used twice.

    • x4740N@lemmy.world
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      7 months ago

      You are right but I do sometimes see that same type of barcode stamped on some Australian letters but I’m not sure what it’s used for

      • x4740N@lemmy.world
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        7 months ago

        They are used internally in post offices but they aren’t exclusive to post offices

    • x4740N@lemmy.world
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      7 months ago

      You are right but I do sometimes see that same type of barcode stamped on some Australian letters but I’m not sure what it’s used for