# Max characters Parameter for Barcode Scanner

**URL:** <https://forum.odk-x.org/t/max-characters-parameter-for-barcode-scanner/2211>\
**Category:** Development\
**Created:** [June 28, 2023, 9:10am UTC](https://forum.odk-x.org/t/max-characters-parameter-for-barcode-scanner/2211 "2023-06-28T09:10:18Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![elmps2018](https://odkx.b-cdn.net/user_avatar/forum.odk-x.org/elmps2018/32/105_2.png) [@elmps2018](https://forum.odk-x.org/u/elmps2018)\
**Post date:** [June 30, 2023, 7:28pm UTC](https://forum.odk-x.org/t/max-characters-parameter-for-barcode-scanner/2211/2 "2023-06-30T19:28:25Z")

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Hi @Harry_Clark ! As you are new to the community, when you get a chance, please introduce yourself [here](https://forum.odk-x.org/t/introduce-yourself/642).

I am not super familiar with barcodes specifically, but in general you can add a constraint to a prompt, and so possibly that would work to constrain the length of the barcode, or the format of the resulting variable. See [ODK-X XLSX Converter Reference — ODK-X Docs](https://docs.odk-x.org/xlsx-converter-reference/?highlight=constraint#optional-columns) for some details on constraints

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