I found this on the internet - it works for Excel - although you say you've used Open Office - not sure it will work on that...
Probably best to generate the barcodes and then batch import them to InDesign.
Let me know if that helps.
Thx Eugene, I will have a look.
But I was kind of hoping to find a solution without having to change anything in excel (OpenOffice).
The list of numbers was given to me by a client. (several hundreds of numbers)
I need to use datamerge in Indd because I also need to number and place several barcodes on 1 page.
Using a font in Indd to generate the barcodes would be the perfect solution.
I suggest trying some Code 128 fonts - a quick search on the internet revealed quite a few, with some recommending not using open type fonts but use true type fonts.
No reason was given, but they recommended that not me.
If it's a font thing - then you just need to find a font that works for your needs.