Look-alikes in digit codes
2026-02-25 · Numeric captchas
O, o, l, I, S, and Z are drawn so they resemble digits. Numeric mode folds them.
Portals use fonts where O is a circle and 0 is a circle. In numeric mode the fold is toward the digit: O and o become 0, l and I become 1, S becomes 5. That is what you want for a digit code and what you do not want for a password made of letters.
Leave uppercase and lowercase unset when you set numeric, unless you have a mixed code. The options section is the exact table.
If a reliable six-digit string is rejected, look at whether the portal was actually mixing letters that day. A mode change is a client fix. Retrying the same mode is not.
Report the id only after you are sure the reading itself was wrong, not the session.
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