Here’s the test:
Which is the letter O as in Oscar and which is the number zero?
In case you couldn’t solve that little puzzle, here are the answers:
- o – little letter
- O – capital letter
- 0 – number
Now imagine a few zeros and letters sprinkled in a large 25 character sequence of random letters and numbers.
This is exactly what I encountered this weekend as I tried to reinstall my Quicken financial software. I had to retype the software activation code and couldn’t distinguish the letter O from the number zero to save my life. Fortunately, after much trial and error, I guessed the right combination of letters and zeros.
On screen or typed, zero and the letter O are nearly impossible to distinguish side by side.
Play it safe and spare your customer some agony and eye strain. Don’t include both zeros and O’s when customers have to identify them on-screen or in printed type. Pay particular attention to activation keys and serial numbers since these random alphanumeric sequences are already very confusing.