Alphanumericals

[1] In the POSIX/C[2] locale, there are either 36 (A–Z and 0–9, case insensitive) or 62 (A–Z, a–z and 0–9, case-sensitive) alphanumeric characters.

When a string of mixed alphabets and numerals is presented for human interpretation, ambiguities arise.

[3] Therefore, depending on the application, various subsets of the alphanumeric were adopted to avoid misinterpretation by humans.

Tiny embossed letters are used to label pins on an V.35/M34 electrical connector.

For alphanumerics that are frequently handwritten, in addition to I and O, V is avoided because it looks like U in cursive, and Z for its similarity to 2.

A black-headed gull ringed with an alphanumeric plastic ring that makes it easier to read from a distance.