Mark, that will work if it is a string.
He did not say if the reade outputs text or a real number.
-Barcode readers typically input text into the computer by emulating a keyboard. It will literally type the number digits into the computer when scanned. This would be the only way supported within Excel.
-representing barcodes as numeric types would be ineffective as any sort of validation would need to convert it to a string to perform a number of string operations.
-Even if the cell type in excel is numeric- which would be the likely default, It doesn't matter what type of data is in the cell. Excel will coerce the data to a text string if necessary. =RIGHT(ATAN(1)*4,7) gives "5358979" for example.
-We know the cell type is almost certainly not numeric as a 12-digit numeric value will be shown via scientific notation which is useless as a barcode.